nas foundations 2005

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Copyright 2005 EMC Corporation. Do not Copy - All Rights Reserved.

NAS Foundations - 1

2005 EMC Corporation. All rights reserved.

NAS FoundationsNAS Foundations

Welcome to NAS Foundations.

The AUDIO portion of this course is supplemental to the material and is not a replacement for the student notes accompanyingthis course. EMC recommends downloading the Student Resource Guide from the Supporting Materials tab, and reading the notes intheir entirety.

Copyright 2005 EMC Corporation. All rights reserved.

These materials may not be copied without EMC's written consent.

EMC believes the information in this publication is accurate as of its publication date. The information is subject to change withoutnotice.

THE INFORMATION IN THIS PUBLICATION IS PROVIDED AS IS. EMC CORPORATION MAKES NO REPRESENTATIONSOR WARRANTIES OF ANY KIND WITH RESPECT TO THE INFORMATION IN THIS PUBLICATION, AND SPECIFICALLYDISCLAIMS IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Use, copying, and distribution of any EMC software described in this publication requires an applicable software license.

Celerra, CLARalert, CLARiiON, Connectrix, Dantz, Documentum, EMC, EMC2, HighRoad, Legato, Navisphere, PowerPath,ResourcePak, SnapView/IP, SRDF, Symmetrix, TimeFinder, VisualSAN, where information lives are registered trademarks.

Access Logix, AutoAdvice, Automated Resource Manager, AutoSwap, AVALONidm, C-Clip, Celerra Replicator, Centera, CentraStar,CLARevent, CopyCross, CopyPoint, DatabaseXtender, Direct Matrix, Direct Matrix Architecture, EDM, E-Lab, EMC AutomatedNetworked Storage, EMC ControlCenter, EMC Developers Program, EMC OnCourse, EMC Proven, EMC Snap, Enginuity, FarPoint,FLARE, GeoSpan, InfoMover, MirrorView, NetWin, OnAlert, OpenScale, Powerlink, PowerVolume, RepliCare, SafeLine, SANArchitect, SAN Copy, SAN Manager, SDMS, SnapSure, SnapView, StorageScope, SupportMate, SymmAPI, SymmEnabler, SymmetrixDMX, Universal Data Tone, VisualSRM are trademarks of EMC Corporation. All other trademarks used herein are the property of theirrespective owners.

All other trademarks used herein are the property of their respective owners.


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NAS Foundations - 2

Upon completion of this course, you will be able to:

2005 EMC Corporation. All rights reserved. Module Title - 2

NAS Foundations

y Identify the concepts and value of Network Attached Storage

y List Environmental Aspects of NAS

y Identify the EMC NAS Platforms and their differences

y Identify and describe key Celerra Software Features

y Identify and describe the Celerra Management Software offerings

y Identify and describe key Windows Specific Options with respect toEMC NAS environments

y Identify and describe NAS Business Continuity and Replication

Options with respect to the various EMC NAS platforms

y Identify and describe key NAS Backup and Recovery options

These are the learning objectives for this training. Please take a moment to read them.


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NAS Foundations - 3


Network Attached Storage

NAS OVERVIEW

Lets start by looking at an overview of Network Attached Storage (NAS).


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NAS Foundations - 4


What Is Network-Attached Storage

y Built on the concept of

shared storage on a LocalArea Network

y Leverages the benefits ofa network file server andnetwork storage

y Utilizes industry-standardnetwork and file sharingprotocols

Network

File Server + Network-attached storage = NAS

Client Application Application Application

Unix Client Unix ClientWindows Client

The benefit of NAS is that it now brings the advantages of networked storage to the desktop through

file-level sharing of data via a dedicated device.

NAS is network-centric. Typically used for client storage consolidation on a LAN, NAS is a preferredstorage capacity solution for enabling clients to access files quickly and directly. This eliminates the

bottlenecks users often encounter when accessing files from a general-purpose server.

NAS provides security and performs all file and storage services through standard network protocols,

using TCP/IP for data transfer, Ethernet and Gigabit Ethernet for media access, and CIFS, http, ftp, and

NFS for remote file service. In addition, NAS can serve both UNIX and Microsoft Windows users

seamlessly, sharing the same data between the different architectures. For client users, NAS is the

technology of choice for providing storage with unencumbered access to files.

Although NAS trades some performance for manageability and simplicity, it is by no means a lazy

technology. Gigabit Ethernet allows NAS to scale to high performance and low latency, making it

possible to support a myriad of clients through a single interface. Many NAS devices support multipleinterfaces and can support multiple networks at the same time.


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NAS Foundations - 5


Why NAS?

y

Highest availabilityy Scales for growth

y Avoids file replication

y Increases flexibility

y Reduces complexityy Improves security

y Costs

Firewall

Web

Servers

NAS

Internet

Data CenterS

n

S2

..

..

S1

Internal

Network

Shared applications can now achieve the availability and scalability benefits of networked storage.

Centralizing file storage reduces system complexity and system administration costs. Backup, restore,

and disaster recovery can be simplified.


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NAS Foundations - 6


NAS Operations

y All IO operations use file level IOprotocols

No awareness of disk volumes ordisk sectors

y File system is mounted remotelyusing a network file accessprotocol, such as: Network File System (NFS)

Common Internet FileSystem(CIFS)

y IO is redirected to remote system

y Utilizes mature data transport

(e.g., TCP/IP) and media accessprotocols

y NAS device assumesresponsibility for organizing data(R/W) on disk and managingcache

Disk

IP Network

App licati on

NAS Device

NAS

SAN

ORDirect

Attach

One of the key differences of a NAS disk device, compared to DAS or other networked storage

solutions such as SAN, is that all I/O operations use file level I/O protocols. File I/O is a high level

type of request that, in essence, specifies only the file to be accessed, but does not directly address the

storage device. This is done later by other operating system functions in the remote NAS appliance.

A file I/O specifies the file. It also indicates an offset into the file. For instance, the I/O may specify

Go to byte 1000 in the file (as if the file were a set of contiguous bytes), and read the next 256 bytes

beginning at that position.

Unlike block I/O, there is no awareness of a disk volume or disk sector in a file I/O request. Inside the

NAS appliance, the operating system keeps track of where files are located on disk. The OS issues a

block I/O request to the disks to fulfill the file I/O read and write requests it receives.

The disk resources can be either directly attached to the NAS device, or they can be attached using a

SAN.


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NAS Foundations - 7


NAS Architecture

Application

Remote I/O

Request

Operating System

NFS/CIFS

TCP/IP Stack

Network Interface

File I/O to NAS

I/O Redirector

Network Interface

TCP/IP Stack

Network FileProtocol Handler

NASOperatingSystem

To Storage

y NFS and CIFS handle

file requests to remotefile system

y I/O is encapsulated byTCP/IP Stack to moveover the network

y NAS device convertsrequests to block IOand reads or writesdata to NAS disk

storage

Drive Protocol (SCSI)

Storage Network

Protocol(Fibre Channel)

The Network File System (NFS) protocol and Common Internet File System (CIFS) protocol handle

file I/O requests to the remote file system, which is located in the NAS device. I/O requests are

packaged by the initiator into the TCP/IP protocols to move across the IP network. The remote NAS

file system converts the request to block I/O, and reads or writes the data to the NAS disk storage. Toreturn data to the requesting client application, the NAS appliance software re-packages the data to

move it back across the network.

Here, we see an example of an IO being directed to the remote NAS device, and the different protocols

that play a part in moving the request back and forth, to the remote file system located on the NAS

server.


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NAS Foundations - 8


NAS Device

y Single-purpose machine orcomponent, serves as a

dedicated, high-performance,high-speed communication of filedata

y Is sometimes called a filer or anetwork appliance

y Uses one or more NetworkInterface Cards (NICs) to connectto the customer network

y Uses proprietary optimizedoperating system; DART, DataAccess in Real Time, is EMCsNAS operating system

y Uses industry standard storageprotocols to connect to storageresources

DiskStorage

IP Network

Client Application

NAS Device

Network Drivers and Protocols

NFS CIFS

NAS Device OS (DART)

Storage Drivers and Protocols

A NAS server is not a general-purpose computer; it is a significantly streamlined/tuned OS, in

comparison to a general purpose computer. It is sometimes called a filer because it focuses all of its

processing power solely on file service and file storage. The NAS device is sometimes called a

network appliance, referring to the plug and play design of many NAS devices. Common networkinterface cards (NICs) include gigabit Ethernet (1000 Mb/s), Fast Ethernet (10Mb/s), ATM, and

FIDDI. Some NAS also supports NDMP, Novell Netware, and HTTP protocols.

The NAS operating system for Network Appliance products is called Data ONTAP. The NAS

operating system for EMC Celerra is DART - Data Access in Real Time. These operating systems

are tuned to perform file operations including open, close, read, write, etc.

The NAS device will generally use a standard drive protocol to manage data to and from the disk

resources.


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NAS Foundations - 9


NAS Applications

y CAD/CAM environments, wherewidely dispersed engineers have

to share and modify designdrawings

y Serving Web pages to thousandsof workstations at the same time

y Easily sharing company-wideinformation among employees

y Database application

Low transaction rate

Low data volatility

Smaller in size

Not performance constrained

Database applications have traditionally been implemented in a SAN architecture. The primary reason

is the deterministic performance of a SAN. This characteristic is especially applicable for very large,

on-line transactional applications with high transaction rates and high data volatility.

However, NAS might be appropriate where the database transaction rate is low and performance is not

constrained. Extensive application profiling should be done in order to understand the specific

database application requirement and if, in fact, a NAS solution would be appropriate.

When considering a NAS solution, the databases should:

ybe sequentially accessed, non-indexed or have a flat file structure

y have a low transaction rate

y have low data volatility

ybe relatively small

y not have performance/timing constraints


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NAS Foundations - 10


NAS Components and Networking Infrastructure

AN INTRODUCTION

This section will introduce NAS components and networking infrastructures.


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What is a Network?

Site 1

Site 2

y LAN

y Physical Media

y WAN

LAN

A network is any collection of independent computers that communicate with one another over ashared network medium. LANs are networks usually confined to a geographic area, such as a single

building or a college campus. LANs can be small, linking as few as three computers, but often linkinghundreds of computers used by thousands of people.

Physical Media

An important part of designing and installing a network is selecting the appropriate medium. There areseveral types in use today: Ethernet, Fiber Distributed Data Interface (FDDI), Asynchronous TransferMode (ATM), and Token Ring.

Ethernet is popular because it strikes a good balance between speed, cost, and ease of installation.These benefits, combined with wide acceptance in the computer marketplace, and the ability to supportvirtually all popular network protocols, make Ethernet an ideal networking technology for mostcomputer users today.

WAN

Wide area networking combines multiple LANs that are geographically separated. This isaccomplished by connecting the different LANs using services such as dedicated leased phone lines,dial-up phone lines (both synchronous and asynchronous), satellite links, and data packet carrierservices. Wide area networking can be as simple as a modem and remote access server for employeesto dial into, or it can be as complex as hundreds of branch offices globally linked, using special routingprotocols and filters to minimize the expense of sending data sent over vast distances.


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Physical Components

y Network Interface

Card (NIC)y Switches

y Routers

NIC

NIC

NIC

NIC

Switch

Switch

Router

155.10.10.XX

155.10.20.XX

Network Interface Card

A network topology is the geometric arrangement of nodes and cable links in a LAN, and is used in

two general configurations: bus and star.Network interface cards, commonly referred to as NICs, are used to connect a Host, Server,

Workstation, PC, etc. to a network. The NIC provides a physical connection between the networking

cable and the computer's internal bus. The rate at which data passes back and forth can be different.

Switches

LAN switches can link multiple network connections together. Todays switches will accept and

analyze the entire packet of data to catch certain packet errors, and keep them from propagating

through the network before forwarding it to its destination. Each of the segments attached to an

Ethernet switch has the full bandwidth of the switch 10Mb/100Mb/1Gigabit.

Routers

Routers pass traffic between networks. Routers also divide networks logically instead of physically.

An IP router can divide a network into various subnets, so that only traffic destined for particular IP

addresses can pass between segments.


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Network Protocols

y Network transport

Protocols

y Network filesystemProtocols

NIC

NIC

NIC

NIC

Switch

Switch

Router

155.10.10.XX

155.10.20.XX

Network transport protocols are standards that allow computers to communicate. A protocol defineshow computers identify one another on a network, the form that the data should take in transit, andhow this information is processed once it reaches its final destination. Protocols also define procedures

for handling lost or damaged transmissions, or "packets".Network transport protocols are used to manage the movement of data packets to devicescommunicating across the network. UDP and TCP are examples of transport protocol. UDP is used innon-connection oriented networks, while TCP is used to manage the movement of data packets inconnection oriented networks.

In a non-connection oriented communication model, the data is sent out to a recipient using a besteffort approach, with no acknowledgement of the receipt of the data being sent back to the originator,by the recipient. Error correction and resend must be controlled by a higher layer application to ensuredata integrity.

In a connection oriented model, all data packets sent by an originator are acknowledged by therecipient, and transmission errors/lost data packets are managed at the protocol layer.

TCP/IP (for UNIX, Windows NT, Windows 95 and other platforms), IPX (for Novell NetWare),DECnet (for networking Digital Equipment Corp. computers), AppleTalk (for Macintosh computers),and NetBIOS/NetBEUI (for LAN Manager and Windows NT networks) are examples of networktransport protocols in use today.

Network filesystem protocols are used to manage how a data request will be processed, once it reachesits final destination. NFS, Network File System protocol, is used to manage file access in a networkedUNIX environment; it is supported by both UDP and TCP transport protocols.

CIFS, Common Internet File system protocol, is used to manage file access in a networked Windowsenvironment, and it is supported by both UDP and TCP transport protocols.


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Network Addressing

y IP Addressing

y DHCP

y DNS

155.10.10.13Host Name Peter

155.10.10.11

Switch

Router

155.10.20.11

DNS Server

155.10.10. 14

Host name Mary

Host Name = Account1

155.10.10.XX

155.10.20.XX

DHCPServer

155.10.10.12

Several things must happen in order for computers, attached to a network, to be able to communicatedata across the network. First, the computer must have a unique network address, referred to as the IPAddress. It is a four octet number in the commonly used IP version 4, for example 155.10.20.11, that

uniquely identifies this computer to all other computers connected to the network.An address can be assigned in one of two ways: dynamically or statically. A static address requiresentering the IP address that the computer will use in a local file. This can be quite a problem from anadministrative view, as well as a source of conflict. If two computers on the same subnet are assignedthe same IP address, they would not be able to communicate. Another approach is to set up a computeron the network to dynamically assign an IP address to a host when it joins the network. This is calledthe Dynamic Host Configuration Protocol (DHCP Server). In our example, the host Mary is assignedan IP address 155.10.10.14, and the host Peter is assigned an IP address 155.10.10.13 by the DHCPserver. The NAS device, Account1, is a File server. Servers normally will have a statically assigned IPaddress. In this example, it has the IP address 155.10.20.11.

A second requirement for communications is to know the address of the recipient of the

communication. The more common approach is to communicate by name, as for example, the nameyou place on a letter. However, the network uses numerical addresses. IP addresses can be managed inthree ways. The first approach is to enter the IP address into the application (IP address in place ofwww.x.com in your browser). The second is to maintain a local file with host names and associated IPaddresses. The third is a hierarchical database called Domain Name Service (DNS), which resolveshost names to IP addresses. In our example, if someone on host Mary wants to talk to host Peter, it isthe DNS server that resolves Peter to 155.10.20.13.


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Volume and Files

y CreateVolumes

y CreateNetworkFilesystem

155.10.10.13Host Name Peter

155.10.10.11

Router

DNS Server

155.10.10. 14Host name Mary

Account1

Array

/Acct_ RepFile System

NAS

155.10.20.11

DHCPServer

155.10.10.12

Create Array Volume

The first step in a network attached storage environment is to create logical volumes on the array and

assign it a LUN Identifier. The LUN will then be presented to the NAS device.Create NAS Volume

The NAS device will perform a discovery operation when it first starts, or when directed. In the

discovery operation, the NAS device will see the array LUN as a physical drive. The next task is to

create logical volumes at the NAS device level. The Celerra will create meta volumes using the

volume resources presented by the array.

Create Network File

When the logical volumes are created on the Celerra, it can use them to create a file system. In this

example, we have created a file system /Acct_Rep on the NAS server Account1.

Mount File System

Once the file system has been created, it must be mounted. With the file system mounted, we can then

move to the next step, which is publishing the file system on the network.


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Publish

y Export

y Share

155.10.10. 13Host name Peter

User PeterUnixExport

155.10.10.11

Router

DNS Server

155.10.10. 14Host name MaryUser MaryMS Windows

Share

Array

ACCOUNT1 /Acct_ Rep

155.10.20.11

Group Name =SALES

Group Name =Accounting

NAS

DHCPServer

155.10.10.12

Now that a network file system has been created, there are two ways it can be accessed using the

network.

The first method is through the UNIX environment. This is accomplished by performing an Export.The Export publishes to those UNIX clients who can mount (access) the remote file system. The

export is published using NFS. Access permissions are assigned when the export is published.

The second method is through the Windows environment. This is accomplished by publishing a share.

The share publishes to those Windows clients who map a drive to access the remote file system. The

share is published using CIFS. Access permission are assigned when the share is published.

In our example, we may only allow Mary and Peter, who are in the Sales organization, share or

export access. At this level, NFS and CIFS are performing the same function, but are used in

different environments. In our example, all members of the Group SALES, which include the users

Mary and Peter, are granted access to /Acct_Rep.


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Client Access

y Mount

y MAP

155.10.10. 13

Host name PeterUser Peter

Unix

nfsmount

155.10.10.11

Router

DNS Server

155.10.10. 14Host name MaryUser Mary

MS Windows

MAP

Array

ACCOUNT1 /Acct_ Rep

155.10.20.11

Group Name =SALES


NAS

DHCPServer

155.10.10.12

To access the network file system, the client must either mount a directory or map a drive pointing to

the remote file system.

Mount is a UNIX command performed by a UNIX client to set a local directory pointer to the remotefile system. The mount command uses NFS protocol to mount the export locally.

For a UNIX client to perform this task, it will execute the nfsmount command. The format for the

command is:

y nfsmount /name of the NAS server:name of the remote file system/name of the local directory

For example:

y nfsmount/Account1:Acct_Rep /localAcct_Rep.

For a Windows client to perform this task, it will execute a map network drive. The sequence is my

computer> tools>map network drive. Select the drive letter and provide the server name and share

name in the Folder field.

For example:

y G:

y \\Account1\Acct_Rep

If you make a comparison, the same information is provided: the local drive (Windows) or the local

directory, the name of the NAS server, and the name of the export or share.


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File Permissions

y Creates File

y File Request

155.10.10. 13

Host name PeterUser Peter

Unix

155.10.10.11

Router

DHCPServerDNS Server

155.10.10. 14Host name MaryUser Mary

MS Windows

155.10.10.12

Array155.10.20.11

Group Name =SALES


Account1

/Acct_ Rep

MRPT1 PRPT2Files

NAS

Creates file

Once access is gained by the client, files can be created on the remote file system. When a file is

created by a client, normal permission is assigned. The Client can also modify the original permissionsassigned to a file. File permission is changed in UNIX using the chmod command. File permission in

Windows is changed through right clicking on the selected file, then selecting Properties> Security,

add or remove group, add or remove permissions. It should be noted that in order to modify the file

permissions, one must have the permission to make the change.

File request

If a request for a file is received by the NAS server, the NAS server will first authenticate the user

either locally, or over the network. If the user identity is confirmed, then the user will be allowed to

perform operations contained in the file permissions for the user of the Group to which the user is a

member.

In our example, user Mary on host Mary creates a file MRPT1 on the NAS server Account1. She

assigns herself the normal permission for this file, which allows her to read and write to this file. She

also limits file permissions to other members of the Group Sales to read only. User Peter on host Peter

is a member of the Group SALES. Peter has access to the export /Acct_Rep. If user Peter attempts to

write to file MRPT1, he would be denied the permission to write to the file.


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EMC NAS Platforms

PRODUCTS

Lets examine the current NAS products offered by EMC.


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EMC NAS Platforms

Broadest Range of NAS Products

CNSNS500NS600NS700

NetWin110

NetWin110, 200

NS704GNS500GNS600GNS700G

High availability

1 or 2 Data Movers

Integrated NAS

CLARiiON

DART

Advanced clu stering

214 Data Movers

NAS gateway to SAN

CLARiiON, Symmetrix

DART

High availability

1 or 2 Data Movers

NAS gateway to SAN

CLARiiON, Symmetrix

DART

Data integrity

Intel-based Server

NAS gateway to SAN

CLARiiON

WSS 2003

Simple Web-based Management

Data integrity

Intel-based Server

NAS direct attach

CLARiiON AX100

WSS 2003

Advanced clu stering

4 Data Movers

NAS gateway to SAN

CLARiiON, Symmetrix

DART

An important decision customers must make is: What is the right information platform that meets my

business requirements?

EMC offers the broadest range of NAS platforms. EMC makes it easy. Rate your requirements andchoose your solution.


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Celerra NAS - SAN Scalability

y Consolidated storage infrastructure

for all applicationsy NAS front end scales independently

of SAN back end Connect to multiple Symmetrix and

CLARiiONs Improved utilization

y Allocate storage to Celerra andservers as needed Easy to move filesystems among Data

Movers Online filesystem growth

y Centralized management for SANand NAS

Windows

UNIX

CLARiiONCX Family

ConnectrixSAN

Celerra

GoldenEagle/Eagle

SymmetrixDMX Family

CelerraNSX00GNSX00GS

One of the reasons that Celerra Golden Eagle scales impressively is due to the architecture thatseparates the NAS front end (Data Movers) from the SAN back end (Symmetrix or CLARiiON).

This allows the front end and back end to grow independently. Customers can merely add Data Moversto the Celerra Golden Eagle to scale the front-end performance to handle more clients. As the amountof data increases, you can add more disks, or the Celerra Golden Eagle can access multiple Symmetrixor CLARiiONs. This flexibility leads to improved disk utilization.

Celerra Golden Eagle supports simultaneous SAN and NAS access to the CLARiiON and Symmetrix.Celerra Golden Eagle can be added to an existing SAN, and general purpose servers can now accessunused back-end capacity. This extends the improved utilization, centralized management, and TCObenefits of SAN plus NAS consolidation to Celerra Golden Eagle, Symmetrix, and CLARiiON.

The configuration can also be reconfigured via software. Since all Data Movers can see the entirefile space, it is easy to reassign filesystems to balance the load. In addition, filesystems can beextended online as they fill.

Even though the architecture splits the front end among multiple Data Movers and a separate SANback end, the entire NAS solution can be managed as a single entity.

The Celerra NSx00G (configured with two Data Movers) and the Celerra NSx00GS (configured with asingle Data Mover) connect to a CLARiiON CX array through a fibre channel switch. CelerraNSx00G/NSx00GS supports simultaneous SAN and NAS access to the CLARiiON CX family.


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Celerra Family Hardware

NAS FRAME BUILDING BLOCKS

Lets take a closer look at the hardware components of the Celerra family.


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Celerra Family Control Station Hardware

y CNS / CFS Style

Control Station

Golden Eagle and

Eagle Frame

Control Station provides the controlling subsystem of the Celerra, as well as the management interface

to all file server components. The Control Station provides a secure user interface as a single point of

administration and management for the whole Celerra solution. Control Station administrative

functions are accessible via the local console, Telnet, or a Web Browser.

The Control station is single Intel processor based, with high memory capacity. Dependent on the

model, the Control Stations may have internal storage. Currently, the NS and Golden Eagle frame

series only have this feature.


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Celerra Family Control Station Hardware (cont.)

y NS Series Style

Disk ArrayEnclosures

This is the NS range Control Station format.


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Celerra Family Data Mover Hardware

y Single or Dual Intel Processors

yPCI or PCI-X based

y High memory capacity

y Multi-port Network cards

y Fibre Channel connectivity tostorage arrays

y No internal storage devices

y Redundancy mechanism

Data Mover

Golden Eagle and Eagle Frame

NS 6XX Frame Data Mover

Each Data Mover is an independent, autonomous file server that transfers requested files to clients and

will remain unaffected, should a problem arise with another Data Mover. The multiple Data Movers

(up to 14 in the Eagle and Golden Eagle frames) are managed as a single entity. Data Movers are hot

pluggable and can be configured with standbys to implement N to 1 availability. A Data Mover (DM)connects to a LAN through FastEthernet, or Gigabit Ethernet. The default name for a Data Mover is

server_n, where n is its slot location. For example, in the Golden Eagle/Eagle frame, a Data Mover

can be in slot location 2 through 15 (i.e. server_2 - server_15 in Celerra Golden Eagle/Eagle frame).

There is no remote login capability on the DM, nor do they run any binaries (very secure).

Data Mover redundancy is the mechanism by which the Celerra family reduces the network data

outage in the event of a Data Mover failure. The ability to failover the Data Movers is achieved by the

creation of a Data Mover configuration database on the Control Station system volumes, and is

managed via the Control Station. No Data Mover failover will occur if the Control Station is not

available for some reason.


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NAS Reference Documentation

y NAS Support Matrix

Data MoversControl Stations

Software supported features

www.emc.com/horizontal/interoperability

The NAS Support Matrix provides support information on the Data Movers and Control Station

models, NAS software version, supported features, storage models, and microcode. This

interoperability reference can be found at: http://www.emc.com/horizontal/interoperability


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Celerra Family Software

SOFTWARE OPERATING SYSTEM

Now, lets look at operating system software used by the Celerra Family.


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Celerra Software Operating Systems

y Linux 7.2This is an industry hardened and EMC modified Operating System loaded

on the Control Station to provide Secure NAS management environmentGrowing in popularity and corporate acceptance

y DART Data Access in Real TimeThis is a highly specialized Operating System designed to optimize network

traffic Input/Output throughput and is loaded on the Data Movers Is multi-threaded to optimize load balancing capabilities of the multi-

processor Data Movers Advanced volume management - UxFS

Large file size and filesystem support Ability to extend filesystems onlineMetadata logging for fast recovery Striped volume support

Feature rich to support the varied specialized capabilities of the Celerrarange

Linux OS is installed on the Control Station. Control Station OS software is used to install, manage,

and configure the Data Movers, monitor the environmental conditions and performance of all

components, and implement the Call Home and dial-in support feature. Typical Administration

functions include volume and filesystem management, configuration of network interfaces, creation offilesystems, exporting filesystems to clients, performing filesystem consistency checks, and extending

filesystems.

The OS that the Data Movers run is EMCs Data Access in Real Time (DART) embedded system

software, which is optimized for file I/O, to move data from the EMC storage array to the network.

DART supports standard network and file access protocols: NFS, CIFS, and FTP.


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Celerra Family

SOME KEY HIGH AVAILABILITY

FEATURES

Lets examine some of the high availability features found in the Celerra family.


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Control Station and Data Mover Standby

y For hardware high availability the EMC NAS frames

implement both Control Station and Data Mover failovercapabilities

yThis means that in the simplest configuration there will bean equivalent system within the frame awaiting a possiblefailure of the active component, in order to assume theconfiguration and production role, with minimal outage tothe end-users

y As the standby system is the equivalent of the productionsystem, there will be no performance or managementimpact to the environment

Hardware high availability is achieved by having equivalent systems contained within the NAS frame

configured as standby units for one or more primary systems.

This is made possible by the configuration database maintained on the Control Station and managedfailover is controlled by the Control Station. A standby system is pointed to a specific location in the

configuration database so that it can assume the complete personality of the failed primary system.

However if the Control Station itself is not available when a primary system fails then failover will not

be able to occur until the Control station is restored.

Standby Data Mover configuration options: 1. Each standby Data Mover, as a standby for a single

primary Data Mover; 2. Each standby Data Mover, as a standby for a group of primary Data Movers;

3. Multiple standby Data Movers for a primary Data Mover. These Standby Data Movers are powered

and ready to assume the personality of their associated Primary Data Movers, in the event of a failure.


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Data Mover Standby (continued)

y Data Mover failover is a policy driven mechanism controlled by theControl Station

yThe policy is as follows

Automatic

When configured like this, the Control Station will detect a Data Mover failure,power down the failed Data Mover and bring the designated standby Data Moveron line with the failed DM personality

Retry

With this configuration, the Control Station will detect a Data Mover failure, tryand reboot the failed Data Mover, if the reboot does not clear the error, powerdown the failed Data Mover and bring the designated standby Data Mover on line

with the failed DM personality Manual

When configured like this no action is taken and administrator intervention isrequired for failover

y In all cases failback is a manual process

How does a Data Mover failover work? Through constant Data Mover monitoring by the Control

Station. This is a policy driven solution and the automatic failover setting of the policy works in the

following fashion:

y the Control Station detects a Data Mover problem

y the failing Data Mover is taken offline

y the pre-defined standby Data Mover assumes the network identity of the failed Data Mover

including the MAC and IP addresses

This process takes seconds to minutes to complete. The standby Data Mover continues serving files to

the failed Data Mover's NFS and CIFS clients. Once the failed Data Mover is replaced, it will resume

its role as the active Data Mover with administrator managed failback, and the standby Data Mover

will resume its standby role.

A single Celerra Data Mover can be configured to act as a standby for several Data Movers. There can

also be many standby Data Movers in a single Celerra cabinet, each backing up their own group ofData Movers. The number of standbys configured depends on how critical the application is and how

much risk can be tolerated.


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Network FailSafe Device

y Network outages, due to environmental failure, are more

common than Data Mover failuresy Network FailSafe Device

DART OS mechanism to minimize data access disruption due tothese failures

Logical device is created using either physical ports, or other logicalports, combined together to create redundant groups of ports

Logically grouped Data Mover network ports monitor network trafficon the ports

Active FailSafe Device port senses traffic disruption

Standby (non-active) port assumes the IP Address and MediaAccess Control address in a very short space of time, thus reducingdata access disruption

Having discussed the maintenance of data access via redundant Data Movers, we will now discuss the sameconcept utilizing network port mechanisms. First, lets look at the Network Failsafe device.

Network outages due to environmental failures are more common than Data Mover failures. To minimize data

access disruption due to these failures, the DART OS has a mechanism, the Network FailSafe Device, which isenvironment agnostic.

This is a mechanism by which the Network ports of a Data Mover may be logically grouped into a partnership,which will monitor network traffic on the ports. If the currently active port senses a disruption of traffic, thestandby (non-active) port will assume the active role in a very short space of time, thus reducing data accessdisruption. The way this works is that a logical device is created, using either physical ports or other logicalports, combined together to create redundant groups of ports.

In normal operation, the active port will carry all network traffic. The standby (nonactive port) will remainpassive until a failure is detected. Once a failure has been detected by the FailSafe Device, this port will assumethe network identity of the active port, including IP Address and Media Access Control address.

Having assumed the failed port identity, the standby port will now continue the network traffic. Networkdisruption due to this change over is minimal, and may only be noticed in a high transaction oriented NASimplementation, or in CIFS environments due to the connection-oriented nature of the protocol.

There are several benefits achieved by configuring the network FailSafe device: 1. Configuration is handledtransparently to client access; 2. the ports that make up the FailSafe device need not be of the same type; 3.Rapid recovery from a detected failure; 4. can be combined with logical Aggregated Port devices to provideeven higher levels of redundancy.

Although the ports that make up the FailSafe device need not be of the same type, care must be taken to ensurethat once failover has occurred, client expected response times remain relatively the same, and data access pathsare maintained.


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Link Aggregation - High Availability

y Link aggregation is the combining of two or more datachannels into a single data channel for high availability

Two Methods: IEEE 802.3ad LACP & CISCO FastEtherChannel

y IEEE 802.3ad LACP

Combining links for improvedavailability

If one port fails, other ports take over

Industry standard IEEE 802.3ad

Combines 212 Ethernet ports intoa single virtual link

Deterministic behavior

Does not increase single client throughput

LINK

IndustryStandardSwitchCelerra

Having discussed the network FailSafe device, the next methodologies we will look at are the two Link

Aggregation methodologies. Link aggregation is the combining of two or more data channels into a

single data channel. There are two methodologies that are supported by EMC NAS devices. They are

IEEE 802.3ad Link Aggregation Control Protocol and CISCO FastEtherChannel using PortAggregation Protocol (PAgP).

The purpose for combining data channels in the EMC implementation is to achieve redundancy and

fault tolerance of network connectivity. It is commonly assumed that link aggregation will provide a

single client with a data channel bandwidth equal to the sum of the bandwidths of individual member

channels. This is not, in fact, the case due to the methodology of channel utilization, and it may only

be achieved with very special considerations to the client environment. The overall channel bandwidth

is increased, but the client will only receive, under normal working conditions, the bandwidth equal to

one of the component channels.

To implement Link Aggregation, the network switches must support the IEEE 802.3ad standard. It is a

technique for combining several links together to enhance availability of network access, and applies

to a single Data Mover, but not across Data Movers. The current implementation focuses on

availability. Only full duplex operation is currently supported. Always check the NAS Interoperability

Matrix for supported features at the following address:

http://www.emc.com/horizontal/interoperability


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Channel

CISCO Switch

Celerra

Link Aggregation - High Availability (continued)

y CISCO FastEtherChannel

Port grouping for improvedavailability

Combines 2, 4, or 8 Ethernetports into a single virtual device

Inter-operates with trunking-capable switches

High availabilityif one port fails,other ports take over

Does not increase single clientthroughput

Ethernet Trunking (Ether Channel) increases availability. It provides statistical load sharing by

connecting different clients to different ports. It does not increase single-client throughput. Different

clients get allocated to different ports. With only one client, the client will access Celerra via the same

port for every access. This DART OS feature interoperates FastEtherChannel capable Cisco switches.FastEtherChannel is Cisco proprietary.

IEEE 802.3ad/FastEtherChannel - Comparison


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Network Redundancy - High Availability

y An example of FSN and Port aggregation co-operation

This example shows a fail-safe network (FSN) device that consists of a FastEtherChannel comprising

the four ports of an Ethernet NIC and one Gigabit Ethernet port. The FastEtherChannel could be the

primary device but, per recommended practices, the ports of the FSN would not be marked primary or

secondary. FSN provides the ability to configure a standby network port for a primary port, and two ormore ports can be connected to different switches. The secondary port remains passive until the

primary port link status is broken, then the secondary port takes over operation.

An FSN device is a virtual device that combines 2 virtual ports. A virtual port can consist of a single

physical link or an aggregation of links (EtherChannel, LACP). The port types, or number, need not be

the same when creating a failsafe device group. For example, a quad Ethernet card can be first

trunked and then coupled with a single Gigabit Ethernet port. In this case, all four ports in the trunk

would need to fail before FSN would implement failover to the Gigabit port. Thus, Celerra could

tolerate four network failures before losing the connection.

Note: an active primary port/active standby port configuration on the Data Mover is not recommended

practice.


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Celerra Family Environment Management

Integration

VIRTUAL LOCAL AREA NETWORKS

Environmental management tools used in the NAS space include Virtual Local Area Networks, or

VLANS. We will now discuss how EMC NAS integrates into this strategy.


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VLAN Support

y Create logical LANsegment

Divide a single LANinto logical segments

J oin multiple separatesegments into onelogical LAN

y VLAN Tagging

802.1q

y Simplified Management

No network

reconfigurationrequired for memberrelocation

Hub Hub

Hub Hub

Bridge

or

Switch

Bridge

or

Switch

Hub Hub

Router

Workstation VLAN B

VLAN B

VLAN A

VLAN A

Collision Domain

LAN Segment

Collision DomainLAN Segment

Collision Domain

LAN Segment

Broadcast Domain

LAN

Broadcast Domain LAN

Network domains are categorized into Collision, a LAN segment within which data collisions arecontained, or Broadcast, the portions of the network through which broadcast and multicast traffic ispropagated. Collision domains are determined by hardware components and how they are connected

together. The components are usually client computers, hubs, and repeaters. Separation of a Collisiondomain from a Broadcast domain is accomplished by a network switch, or a router, that generally doesnot forward broadcast traffic. VLANs allow multiple, distinct, possibly geographically separatenetwork segments to be connected into one logical segment. This can be done either by subnetting orby using VLAN tags (802.1q.), which is an address added to network packets to identify the VLANs towhich the packet belongs. This could allow servers that were connected to physically separatenetworks to communicate more efficiently, and it could prevent servers that were attached to the samephysical network from impeding one another.

By using VLANs to logically segment the Broadcast Domains, the equipment contained within thislogical environment need not be physically located together. This now means that if a mobile clientmoves location, an administrator need not do any physical network or software configuration for the

relocation, as bridging technology would now be used, and a router would only be needed tocommunicate between VLANS.

There are two commonly practiced ways of implementing this technology:

. IP Address subnetting

. VLAN Ethernet packet tagging


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VLAN Implementation Methodologies

yThere are two primary methodologies of implementing

VLANSBy IP address subnetting

Using this methodology an administrator will configure the broadcastdomains to encompass the whole network area for specific groups ofcomputers, by using BridgeRouter technology

By VLAN Tagging

Using this methodology an administrator will configure groups of usercomputers to embed an identification tag embedded into all of theirEthernet packet traffic

When using the IP address subnetting methodology, the administrator will configure the broadcast

domains to encompass the whole network area for specific groups of computers, by using

BridgeRouter technology. When using the VLAN tagging methodology, the members of a specific

group will have an identification tag embedded into all of their Ethernet packet traffic.

VLAN Tagging allows a single Gigabit Data Mover port to service multiple logical LANs (Virtual

LANs). This allows data network nodes to be configured (added and moved as well as other changes)

quickly and conveniently from the management console, rather than in the wiring closet. VLAN also

allows a customer to limit traffic to specific elements of a corporate network, and protect against

broadcasts (such as denial of service) affecting whole networks. Standard router based security

mechanisms can be used with VLANs to restrict access and improve security.


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VLAN - Benefits

y Performance

This is client related as

packets not destined for amachine in a particular VLANwill not be processed by theclient

y Reduced Router Overhead

y Reduced Costs

expensive routers and billabletraffic routing costs can bereduced

y Security

placing users into a taggedVLAN environment willprevent unauthorized accessto network packets

VLAN-A VLAN S VLAN E

The benefits of VLAN support include:

y Performance: In all networks, there is a large amount of broadcast and multicast traffic and

VLANS can reduce the amount of traffic being processed by all clients.

y Virtual Collaborative Work Divisions: by placing widely dispersed collaborative users into a

VLAN, broadcast and multicast traffic between these users will be kept from affecting other

network clients, and reduce the amount of routing overhead placed on their traffic.

y Simplified Administration: with the large amount of mobile computing today, physical user

relocation generates a lot of administrative user reconfiguration (adding, moving and changing). If

the user has not changed company functionality, but has only relocated, VLANs can perpetuate

undisrupted job functionality.

y Reduced Cost by using VLANS: expensive routers and billable traffic routing costs can be

reduced.

y Security, by placing users into a tagged VLAN environment, external access to sensitive broadcast

data traffic can be reduced.

VLAN support enables a single Data Mover with Gigabit Ethernet port(s) to be the standby for

multiple primary Data Movers with Gigabit Ethernet port(s). Each primary Data Mover's Gigabit

Ethernet port(s) can be connected to different switches. Each of these switches can be in a different

subnet and different VLAN. The standby Data Mover's Gigabit Ethernet port is connected to a switch

which is connected to all the other switches.


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Celerra Family Software Management

USER INTERFACES

In this section, we will examine the different user interfaces. These interfaces include the Command

line, Celerra Manager, and EMC ControlCenter.


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Celerra Management Command Line

yThe command line can be accessed on the ControlStation viaAn ssh interface tool, e.g. PuTTy

Telnet

y Its primary function is for the scripting of commonrepetitive tasks that may run on a predeterminedschedule to ease administrative burden

y It has approximately 60 UNIX command-like commandsnas_ - These commands are generally for the configuration and

management of global resourcesserver_- These commands are generally for the configuration and

management of Data Mover specific resources

Telnet access is disabled, by default, on the Control Station due to the possibility of unauthorized

access if the Control Station is placed on a publicly accessible network. If this is the case, it is strongly

recommended that this service is not enabled.

The preferred mechanism of accessing the Control Station is the SSH (Secure Shell) daemon via an

SSH client such as PuTTy.


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Celerra Manager GUI Management

With the release of DART v5.2, the GUI management has become consolidated into one product with

two options:

y Celerra Management Basic Edition

y Celerra Management Advanced Edition

The Basic Edition will be installed, along with the DART OS, and will provide a comprehensive set of

common management functionality for a single Celerra at a time. The Advanced Edition will add

multiple Celerra support, along with some advanced feature GUI management, and will be licensed

separately from the DART code.


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Celerra Manager GUI Wizards

Celerra Manager V5.2 and higher will offer a number of configuration Wizards for various tasks to

assist with new administrator ease of implementation.


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Celerra Manager GUI Tools

Celerra Manager V5.2 will offer a set of tools to integrate Celerra monitoring functionality and launch

Navisphere Manager.

With the addition of the Navisphere Manager Launch capability, the SAN/NAS administrator willhave a more consolidated management environment.


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EMC ControlCenter V5.x.x NAS Support

y Discovery and monitoring

Data Movers

Devices and volumes

Network adapters and IPinterfaces

Mount points

Exports

Filesystems (including snapshotsand checkpoints)

The EMC flagship management product, EMC ControlCenter, has the capability of an assisted

discovery of both EMC NAS and third party NAS products, namely NetApps filers.

Currently, management of the EMC NAS family is deferred to the specific product managementproducts, due to the highly specialized nature of the NAS environment. Therefore, this product

functionality (shown on this slide) is focused mainly around discovery, monitoring, and product

management software launch capability

ControlCenter V5.x.x has enhanced device management support for the Celerra family. The

ControlCenter Celerra Agent runs on Windows and has enhanced discovery and monitoring

capabilities. You can now view properties information on Celerra Data Movers, devices, network

adapters and interfaces, mount points, exports, filesystems (including snapshots and checkpoints), and

volumes from the ControlCenter Console. You can also view alerting information for the Celerra

family as well.


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Celerra Family File System Management

AUTOMATIC VOLUME MANAGEMENT

For ease of use and implementation, the DART operating system utilizes an Automatic Volume

Manager (AVM). This allows the NAS manager to quickly create, deploy and manage NAS file

systems with known, predictable performance and management parameters.


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Celerra Automatic Volume Management - AVM

y Celerra uses AVM to create a more array friendlymethodology for laying out volumes and file systems

Automates volume and file system creation and management

Arranges volumes into storage pools dependent upon the array disklayout characteristics

System defined

Profiles are predefined rules that define how devices are aggregated and put intosystem-defined storage pools

User defined

This storage pools allow customers more flexibility to define their own volumecharacteristics to meet their own specific needs

y Volume creation from the GUI management interface willuse AVM by default, but it can also be invoked from theCommand Line Interface, CLI

The Automatic Volume Management (AVM) feature of the Celerra File Server automates volumecreation and management. By using Celerra command options and interfaces that support AVM, youcan create and expand file systems without manually creating and managing their underlying volumes.

A Storage Pool is a container for one or more member volumes. All storage pools have attributes,some of which are modifiable. There are two types of storage pools:y System-defined System-defined storage pools with NAS 5.3 are what used to be called systemprofiles in prior releases. AVM controls the allocation of storage to a file system when you createthe file system by allocating space from a system-defined storage pool. The system-definedstorage pools ship with the Celerra. They are designed to optimize performance based on thehardware configuration.

y User-defined User-defined storage pools allow for more flexibility in that you choose whatstorage should be included in the pool. If the user defines the storage pool, the user must explicitlyadd and remove storage from the storage pool and define the attributes for the storage pool.

Profilesprovide the rules that define how devices are aggregated and put into system-defined storagepools. Users cannot create, delete, or modify these profiles. There are two types of profiles:

y Volume Volume profiles define how new disk volumes are added to a system-defined storagepool.

y Storage Storage profiles define how the raw physical spindles are aggregated into Celerra diskvolumes.

Note: Both volume profiles and storage profiles are associated with system-defined storage pools andare unique and predefined for each storage system. It is NOT recommended to mix the types of volumemanagement methodologies, AVM and Manual, on a system, as mixing these may result in non-optimized disk utilization leading poor system utilization and performance.


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AVM System Defined Storage Pools

y symm_std

Highest performance, medium cost, using Symmetrix STD disk volumes

y symm_std_rdf_src

Highest performance, medium cost, using SRDF

y clar_r1

High performance, low cost, using CLARiiON CLSTD disk volumes in RAID 1

y clar_r5_performance

Medium performance, low cost, using CLARiiON CLSTD disk volumes in 4+1RAID 5

yclar_r5_economy Medium performance, lowest cost, using CLARiiON CLSTD disk volumes in 8+1

RAID 5

y clarata_archive

6+1, low performance, high capacity, using CLARiiON Serial ATA disk volumes

STD = Standard

CLSTD = CLARiiON Standard

Clarata = CLARiiON ATA drives


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Celerra Family Management Software

WINDOWS SPECIFIC INTEGRATION

OPTIONS

EMC NAS frames integrate traditionally into UNIX environments seamlessly due to its roots in the

NFS protocol environment. However, with the addition of support for the CIFS protocol, which is the

Microsoft networking domain, there has been the need for very specific integration methodologies to

ensure the seamless integration and management into this environment.


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Windows Environment Integration

yTo achieve a tightly integrated Windows active directoryenvironment, EMC NAS uses several software features

usermapper

This is a feature that will help the Celerra automatically assign UNIXuser and group identifiers, UIDs and GIDs, to Windows users andgroups. This assists Windows administrators with the integration of thesespecialized NAS frames, as there is minimal or no user environmentmodification

UNIX User Management

Active Directory migration tool

MMC plug-in extension for ActiveDirectory uses and computers

Celerra Management tool snap-in

(MMC Console)

Celerra offers a number of Windows 2000 management tools with the Windows 2000 look and feel.

For example, Celerra shares and quotas can be managed by the standard Microsoft Management

Console (MMC).

The tools include:

y The Active Directory (AD) Migration tool Migrates the Windows/UNIX user and group

mappings to Active Directory. The matching users/groups are displayed in a property page with a

separate sheet for users and groups. The administrator selects the users/groups that should be

migrated and de-selects those that should not be migrated, or should be removed from Active

Directory.

y The Microsoft Management Console (MMC) Snap-in extension for AD users and computers.

This adds a property page to the users property sheet to specify UID (user ID)/GID (group

ID)/Comment and adds a property page to the group property sheet to specify GID/Comment. You

can only manage users and groups of the local tree.

y The Celerra Management Tool (MMC Console) Snap-in extension for Dart UNIX User

Management displays Windows users/groups which are mapped to UNIX attributes. It also

displays all domains that are known to the local domain (Local Tree, Trusted domains).


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Windows Environment Integration (continued)

Virus Checker Management

Celerra Management tool

MMC Console

Home Directory snap-in

Allows multiple points of entry to a single share

Data Mover security snap-in

Manage user rights and auditing

Further tools are

y The Celerra Management Tool (MMC Console)Snap-in extension for Dart Virus Checker

Management which manages parameters for the DART Virus Checker.

y The Home Directories capability in the Celerra allows a customer to set up multiple points of entry

to a single Share/Export so as to avoid sharing out many hundreds of points of entry to a

filesystem, for each individual user for storing their Home Directories. The MMC Snap-in provides

a simple and familiar management interface for Windows administrators for this capability.

y The Data Mover Security Settings Snap-in provides a standard Windows interface for managing

user rights assignments, as well as the settings for which statistics Celerra should audit, based on

the NT V4 style auditing policies.


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Virtual Data Movers

y Another improvement to the Windows integration is the

ability to create multiple virtual CIFS servers on eachData Mover

yThis is achieved by creating Virtual Data Moverenvironments

This is a huge benefit to the consolidation of multiple server, fileserving functionality onto single Data Movers, as each virtual DataMover can maintain isolated CIFS servers with their own rootfilesystem environment

This will allow whole Virtual Data Mover environments to be loaded,unloaded, or even replicated between physical Data Movers for easein Windows environmental management

Currently, in pre DART v5.2, a Data Mover supports one NFS server and multiple CIFS servers, whereeach server has the same view of all the resources. The CIFS servers are not logically isolated andalthough they are very useful in consolidating multiple servers into one data mover, they do notprovide the isolation between servers as needed in some environments, such as data from disjoint

departments hosted on the same data mover.

In v5.2, VDMs support separate isolated CIFS servers, allowing you to place one or multiple CIFSservers into a VDM, along with their file systems. The servers residing in a VDM store their dynamicconfiguration information (such as local groups, shares, security credentials, and audit logs, etc.) in aconfiguration file system. A VDM can then be loaded and unloaded, moved from Data Mover to DataMover, or even replicated to a remote Data Mover as an autonomous unit. The servers, their filesystems, and all of the configuration data that allows clients to access the file systems are available inone virtual container.

VDMs provide virtual partitioning of the physical resources, and independently contain all theinformation necessary to support the contained CIFS servers. Having the file systems and theconfiguration information contained in a VDM does the following:

y enables administrators to separate CIFS servers and give them access to specified shares;

y allows replication of the CIFS environment from primary to secondary without impacting serveraccess;

y enables administrators to easily move CIFS servers from one physical Data Mover to another.

A VDM can contain one or more CIFS servers. The only requirement is that you have at least oneinterface available for each CIFS server you create. The CIFS servers in each VDM have access onlyto the file systems mounted to that VDM, and therefore can only create shares on those file systemsmounted to the VDM. This allows a user to administratively partition or group their file systems andCIFS servers.


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Celerra Family Business Continuity

DISK BASED REPLICATION AND

RECOVERY SOLUTIONS

Now we can examine some of the replication and recovery solutions available in the Celerra family.


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Disk-Based Replication and Recovery Solutions

Celerra/Symmetrix

Celerra/FC4700

SynchronousSynchronousDisasterDisasterRecoveryRecovery

SRDFSRDF

Seconds

FileFile

RestorationRestorationCelerra SnapSureCelerra SnapSure

Hours

FileFile--basedbasedReplicationReplicationTimeFinder/FSTimeFinder/FS

Celerra ReplicatorCelerra ReplicatorEMC OnCourseEMC OnCourse

Minutes

Celerra /CLARiiON

CelerraNS600

FUNCTIONALITY

RECOVERY TIME

High-end environments require non-stop access to the information pool. From a practical perspective,not all data carries the same value. The following illustrates that EMC Celerra provides a range ofdisk-based replication tools for each recovery time requirement.

File restoration: This is the information archived to disk and typically saved to tape. Here we measurerecovery in hours. Celerra SnapSure enables local point-in-time replication for file undeletes andbackups.

File-based replication: This information is recoverable in time frames measured in minutes.Information is mirrored to disk by TimeFinder, and the copy is made accessible with TimeFinder/FS.The Celerra Replicator creates replicas of production filesystems either locally, or at a remote site.Recovery time from the secondary site depends on the bandwidth of the IP connection between the twosites. EMC OnCourse provides secure, policy-based file transfers.

The Replicator feature supports data recovery for both CIFS and NFS by allowing the secondaryfilesystem (SFS) to be manually switched to read/write mode after the Replicator session has beenstopped, either manually or due to a destructive event. Note: There is no re-synch or failbackcapability.

Synchronous disaster recovery: this is the information requiring disaster recovery with no loss oftransactions. This strategy allows customers to have data recovery in seconds. SRDF, in synchronousmode, facilitates real-time remote mirroring in campus environments (up to 60 km).

File restoration and file-based replication (Celerra Replicator, EMC OnCourse) are available withCelerra /CLARiiON. The entire suite of file restoration, file-based replication, and synchronousdisaster recovery are available with Celerra /Symmetrix.


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Disaster Recovery

CELERRA SYMMETRIX REMOTE DATA

FACILITY

In this section, we will look at the Celerra disaster recovery solution.


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Celerra SRDF Disaster Recovery

y Celerra synchronous disaster recovery solution Allows an administrator to configure remote standby Data Movers, waiting

to assume primary roles, in the event of a disaster occurring at the primarydata site

SRDF allows administrator to achieve a remote synchronous copy ofproduction filesystems at a remote location

Real-time, logically synchronized and consistent copies of selected volumes Uni-directional and bi-directional support Resilient against drive, link, and server failures No lost I/Os in the event of a disaster Independent of CPU, operating system, application, or database Simplifies disaster recovery switchover and back

CelerraCelerraUni or bi-directional

Campus (60 km) distance

Network

Increases data availability by combining the high availability of theCelerra family with the Symmetrix Remote Data Facility

In the NAS environment, data availability is one of the key aspects for implementation determination.By combining the high availability of the Celerra family with the Symmetrix Remote Data Facility,data availability increases exponentially. What the SRDF feature allows an administrator to achieve is

a remote synchronous copy of production filesystems at a remote location. However, as this entails thecreation of Symmetrix specific R1 and R2 data volumes, this functionality is currently restricted toCelerra/Symmetrix implementations only. This feature allows an administrator to configureremote standby Data Movers waiting to assume primary roles in the event of a disaster occurring at theprimary data site. Due to data latency issues, this solution is restricted to a campus distance ofseparation between the two data sites (60 network km). The SRDF solution for Celerra can leverage anexisting SRDF transport infrastructure to support the full range of supported SAN (storage areanetwork) and DAS (direct-attached storage) connected general purpose server platforms.

After establishing the connection and properly configuring the Celerra, users gain continued access tofilesystems in the event that the local Celerra and/or the Symmetrix becomes unavailable. The Celerrasystems communicate over the network to ensure the primary and secondary Data Movers are

synchronized with respect to meta data, while the physical data is transported over the SRDF link. Inorder to ensure an up to date and consistent copy of the filesystems on the remote Celerra, thesynchronous mode of SRDF operation is currently the only supported SRDF operational mode, butboth modes of SRDF operation, active-passive and active-active, are supported. This means that activedata can be configured to be only on one side of the SRDF link or on both sides, dependent on thecustomers needs.


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Data Replication

SNAPSURE, TIMEFINDER/FS &

CELERRA REPLICATOR

Next, we will examine several of the Celerra data replication solutions.


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Celerra SnapSure - Data Replication

y Enables speedy recovery

Low volume activity, read-onlyapplications

Simple file undelete

Incremental backup

y Logical point-in-time view ofCelerra data Works for all Celerra

Implementations

Saves disk space

Maintains pointers to track changesto the primary filesystem

Not a mirror; creation of specializedvolumes (R1/R2, BCVs) notrequired

Productionfilesystem Checkpoint

Celerra CLARiiON orSymmetrix

Due to the business demands for high data availability and speedy recovery, there are many

methodologies utilized to facilitate this requirement.

The first methodology discussed is the SnapSure feature of the Celerra family. This methodology usesa logical point-in-time view of a Production Filesystem to facilitate Incremental backup views of a

Production File System, PFS, individual file recovery, and roll back of an entire filesystem to a

previous point-in-time image. SnapSure maintains pointers to changes to the primary file system, and

reads data from either the primary filesystem or a copy area. The copy area is defined as a meta-

volume (SavVol).

One of the obvious benefits of this solution is that it is storage array agnostic, i.e. works for all NAS

DART implementations. This also means that there are no specialized volumes that need to be

configured for this feature to function. Some other replication methodologies, such as SRDF and

TimeFinder/FS, are dependent on the creation of Symmetrix Remote Data Facility and Business

Continuity Volumes in the Symmetrix. SnapSure does not require any specialized volume creation and

will therefore work with any back-end storage array (CLARiiON or Symmetrix).

Multiple Checkpoints can be done on the Production Filesystem and, thereby, facilitate the ability to

recover different point-in-time images of files or filesystems. Without using any other similar

replication methodologies, e.g. Celerra Replicator, the currently supported maximum of Checkpoints

per filesystem is 32.


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Celerra SnapSure - Management

yMultiple Checkpoints for recovery of different point-in-time

imagesGUI Checkpoint schedule manipulation

Checkpoint out of order delete

Automatic mounting upon creation

For ease of management, Checkpoints can be manipulated with the GUI management interfaces, along

with the ability to schedule the frequency of the Checkpoints.

Most Checkpoint technology is chronologically linked; however, the DART 5.2 solution will supportout of order deletion of checkpoints, while maintaining SnapSure integrity. SnapSure Enhancements

allow customers to delete a Checkpoint out of order. This feature allows customers to delete any

Checkpoint instead of being constrained to having to delete Checkpoints from the oldest to maintain

integrity.

A customer may also delete an individual scheduled checkpoint instead of the entire schedule, and may

refresh any checkpoint instead of only the oldest.

Checkpoints created in DART v5.2 are automatically mounted on creation, and maintenance of a

hidden checkpoint directory in any subdirectory. This new hidden directory will now also allow

changing the default name (yyy_dd_hh_mm_ss_GMT) into something more administratively friendly.


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Celerra TimeFinder/FS - Data Replicationy Point in time copy of file system

y Provides an independent mirror copy ofCelerra data for out-of-bandbusiness

processes and support functionsy Provides read and write functionality

independent of the original

y Requires Symmetrix storage

y Celerra controlled features Point-in-time copies

Dynamic mirroring

Multiple BCVs

Spans volumes

Entire filesystem

y Applications Backup and restore

Data warehouses

Live test data

Batch jobs

BCV =Business Continuance Volume

Point-in-timecopy

CelerraSymmetrix

FSAFSAPFS

PFSCopy

A second Celerra data replication method that provides high availability and rapid recovery is

TimeFinder/FS. It uses a specially defined volume, called a Business Continuance Volume (BCV), to

facilitate this functionality. As only the Symmetrix Array is currently able to define a BCV,

TimeFinder/FS on the Celerra Family is currently restricted to implementations with Symmetrix only.The TimeFinder/FS implementation is different from a standard TimeFinder implementation as it is

file system based, which is implemented upon a volume based feature. A BCV, which attaches to a

standard volume on which a file system resides, provides the foundation for the file system copy. File

systems can share BCVs, although the BCV remains dedicated to a volume. What this means is that if

multiple file systems share a single BCV when one of the file systems is saved as point in time, all

other file systems are in an unknown state. This, therefore, precludes the ability for recovery from this

copy as the unknown state file systems would also be recovered and the underlying technology is

volume based.

TimeFinder/FS creates a point-in-time copy, or a dynamic mirror, of a filesystem. Integrated into the

Celerra Control Station. The TimeFinder/FS option allows users to create filesystem copies (with onlya brief suspension of access to the original file system), for independent read/write copies of data,

useful for non-disruptive file backups, live copy test beds for new applications, and mirror copies of

files for redundancy and business continuity. It will facilitate backup and restore of older versions of a

specific file, directory, (by mounting the snapshot filesystem and manually recovering the file or

directory) or complete file system. It can also function in mirroring and continuous updates mode for

an active file system.


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TimeFinder/FS Near Copy

y Synchronous disk-based disasterrecovery and data replication

solution

Requires Symmetrix storage

nas foundations 2005

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