edison ibm storwize v7000 cmcs white paper

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White Paper

Competitive Management Cost Study:

IBM Storwize V7000 vs. EMC VNX5500

Storage Systems

Printed in the United States of America.

Copyright 2012 Edison Group, Inc. New York. Edison Group offers no warranty either expressed or

implied on the information contained herein and shall be held harmless for errors resulting from its use.

All products are trademarks of their respective owners.

First Publication: April 2012

Produced by: Kalicharan Rakam, Senior Analyst, Craig Norris, Writer; Barry Cohen, Senior Analyst,

Editor-in-Chief; Manny Frishberg, Editor

Table of Contents

Executive Summary ..................................................................................................................... 1

About This White Paper ............................................................................................................. 4

Who Should Read This White Paper ................................................................................... 4

Methodology Overview......................................................................................................... 4

Contents of this White Paper ................................................................................................ 4

Storage Management Costs in the Data Center ..................................................................... 5

Overview of the Products ........................................................................................................... 6

Overview of the Management Consoles ............................................................................. 7

Results Summary ....................................................................................................................... 13

Comparative Management Cost Savings .......................................................................... 15

Results Details ............................................................................................................................ 18

Provisioning .......................................................................................................................... 18

Data Protection ..................................................................................................................... 21

Maintenance and Configuration Changes ........................................................................ 24

Monitoring ............................................................................................................................. 27

Methodology for This Study ................................................................................................... 31

CMCS Methodology............................................................................................................. 31

Laboratory Configuration ................................................................................................... 31

Test Procedures ..................................................................................................................... 33

GUI vs. CLI ............................................................................................................................ 34

Other Considerations ........................................................................................................... 36

How to Use These Results ................................................................................................... 36

Conclusions ................................................................................................................................. 37

Appendices .................................................................................................................................. 38

Appendix I - CMCS Methodology Description ................................................................ 38

Appendix II - Terminology Glossary ................................................................................. 42

Edison: Comparing Management Costs for IBM Storwize V7000 and EMC VNX5500 Page 1

Executive Summary

As it has been the trend over the last decade, organizations must continue to deal with

growing data storage requirements with the same or less resources. 1 The growing

adoption of storage-as-a-service, business intelligence, and big data results in ever more

Service Level Agreements that are difficult to fulfill without IT administrators spending

ever longer hours in the data center. Many organizations now expect their capital

expense growth for storage to be unstoppable, and see operating expense levers — such

as purchasing storage systems that are easy to manage — as the only way to control data

storage-related costs.

Edison’s Competitive Management Cost Study (CMCS) methodology was designed

based on Edison’s research over several years. It quantifies the complexity of managing

a storage array in a way that easily translates into operational expense. The present

study applies this methodology in comparing the relative complexity and ease-of-use of

management consoles for two storage systems built for mid-sized organizations: IBM

Storwize V7000 and EMC VNX5500. While the two products compared in this study are

both unified storage systems, this study specifically evaluated only their block-based

storage features.

The results of Edison’s research show that administering the IBM Storwize V7000 system

using its management interface is 34 percent less time-consuming in weighted workday

savings and 31 percent less complex than managing an EMC VNX5500 system using the

Unisphere software interface. These results are displayed graphically in the following

graphs.

1 Gartner Expects Mild IT Spending Growth in 2011, Enterprise Storage Forum.com

http://www.enterprisestorageforum.com/industrynews/article.php/3909076/Gartner-Expects-Mild-IT-Spending-Growth-in-2011.htm


Using storage administrator-workload weighting factors developed by Edison, these

time savings can be evaluated in terms of operating expense (OPEX) savings. This

assessment demonstrates a 34 percent improvement 2 in storage administrator efficiency

from IBM Storwize V7000 over EMC VNX5500.

Monetizing these efficiencies can result in cost savings of more than $25,000 per year

with IBM Storwize V7000 over EMC VNX5500.

2 Presented in Table 1 of this report: Storwize V7000 CMCS Summary of Results.


About This White Paper

This white paper is based on a combination of hands-on evaluation, review of relevant

published documents on storage cost of ownership, and reports on data center and

storage administrator salaries.

Who Should Read This White Paper

This white paper should be read by anyone responsible for choosing storage solutions

for their organizations or for making administrative personnel decisions in the data

center.

Methodology Overview

Edison performed the series of tasks described in this white paper on storage systems

from IBM and EMC. The methodology and specifications for the hardware and software

evaluated are listed in the section of this paper entitled “Methodology for This Study.”

NOTE The two products compared in this study are both unified storage systems.

However, this study specifically evaluated only their block-based storage features.

Contents of this White Paper

Executive Summary – a summary of the context for and results of Edison’s research.

Storage Management Costs in the Enterprise – overview of the factors affecting

storage management costs and a discussion of the products tested in this study.

Overview of the Products – description of the products evaluated in this study and

the management software user interface for each.

Results Summary – summary of the overall results of the evaluation.

Results Details – discussion of the results for each task category evaluated.

Methodology for This Study – overview of the methodology Edison used in

performing the hands-on research.

Conclusions – summary of the results of Edison’s research.

Appendices – a more detailed discussion of the evaluation methodology and a

terminology glossary.


Storage Management Costs in the Data Center

Edison Group has developed the Competitive Management Cost Study (CMCS)

methodology for applying hands-on research comparing administrative consoles of

storage systems to determine how their relative ease of use affects the ownership costs of

each system. Edison’s CMCS analyses have been used to evaluate administrative

consoles for mid-range storage systems from major vendors such as HP, NetApp, EMC,

and now from IBM.

New trends and developments, such as uncontrolled capacity growth, virtualization,

and facility costs, affect acquisition decisions for storage systems. The exponential

growth in capacity requirements is widely acknowledged. Storage virtualization, too,

has become accepted as the standard approach for storage systems of all sizes, from

Data Robotics, Inc.'s Drobo SOHO arrays to the largest enterprise systems from IBM,

EMC, HP, and NetApp. Similarly, server virtualization is being widely deployed:

according to executives at VMware, the largest vendor of server virtualization on the

x86/x64 platform, there are now more virtual servers running under VMware than

physical servers.

As for facilities costs, even with increased drive capacities and storage consolidation via

virtualization, growing capacity requirements still translate into growing expenses.

The inexorable growth of application demand and data retention requirements is

driving the need to control the cost of managing storage systems, by far the most

significant OPEX cost-control lever that exists. In the years since Edison developed our

first CMCS report on managing mid-range systems, many storage vendors have made

strides in addressing the costs of management complexity by improving their

management software. This report covers a comparison between the currently available

IBM Storwize V7000 storage system and EMC VNX.


Spotlight on Automated Tiering

This paper focuses on time and complexity

savings through the management software

of the products. Worth noting, though, is

that IBM Storwize V7000 also has features,

including automatic tiering, virtualized

pooling and virtualization of external

storage systems, which can make the most

effective use of storage resources, enhancing

performance and reducing OPEX. IBM

Storwize V7000 allows any combination of

supported heterogeneous storage devices to

be enlisted in a single virtualized pool that

can be accessed regardless of underlying

hardware resources.

Specific types of data can also be assigned

to appropriate types of storage. For

instance, data for applications that require

extremely fast response times can be

assigned to solid-state drives (SSDs), while

data requiring less demanding access

speeds can be stored on less costly

traditional spinning disk drives. Using IBM

System Storage Easy Tier technology,

frequently-used data can be automatically

moved to high performance SSDs based on

ongoing performance monitoring. This

approach enables an organization to benefit

from SSD technology at lower cost than an

all-SSD solution, yet without requiring

administrators to create and manage

storage tier policies. A similar technology

from EMC (FAST) is not nearly as granular

as EasyTier and, therefore, not as efficient.

Overview of the Products

The products evaluated for this white paper represent the latest generation of mid-range

storage products, designed for medium-sized to enterprise businesses, from IBM and

EMC. Data centers frequently deploy Storage Area Network (SAN) storage systems for

applications requiring the highest levels

of performance, while separately

deploying Network Attached Storage

(NAS) for its ease of use and less

expensive networking. This approach

adds to complexity, introducing multiple

points of management and creating

islands of storage, which have adverse

impacts on efficiency.

Both products evaluated in this study are

designed to provide a single solution that

is more affordable and less complex to use

than higher-end storage. Powered by Intel

Xeon processors, both incorporate such

advanced technology as virtualized

storage, thin provisioning, and tiering to

help close the gap between exponential

data growth and IT storage budgets.

IBM Storwize V7000

Storwize V7000 combines hardware and

software components to help support

improved storage efficiency through a

single point of control. It is designed to

improve application availability and

resource utilization via a variety of

technologies including thin provisioning,

automated tiering, storage virtualization

(internally and externally), clustering,

replication, multi-protocol support, and a

robust, intuitive Graphical User Interface

(GUI).


The storage system is packaged in 2U rack-mountable enclosures that house up to 24

2.5-inch drives or up to 12 3.5-inch drives. Control enclosures contain drives, redundant

dual-active intelligent RAID controllers, dual power supplies, batteries, and cooling

components. Expansion enclosures contain drives, switches, power supplies, and

cooling components. Control enclosures can be clustered and up to nine expansion

enclosures can be attached to a control enclosure, supporting up to 240 drives.

Tasks related to out-of-the-box product installation and setup were not evaluated for

this study. However, the relative simplicity of the IBM Storwize V7000 initialization is

worth noting here. The IBM Storwize V7000 initiation employs a USB dongle: the

administrator sets the IP address, inserts the dongle, and initial discovery and

provisioning takes place, speeding deployment and reducing initial setup costs.

EMC VNX5500

EMC replaced its former CLARiiON and Celerra product lines with new models under

the VNX brand. These new storage systems combine many of the features of CLARiiON

and Celerra and include several hardware changes, including an update to the Intel

processor in the controller. In addition, EMC has joined the transition from 3.5-inch FC

drives to 2.5-inch SAS drives as the new standard for high performance enterprise-class

spinning disks. 3

The storage system is packaged in rack-mountable enclosures that house up to 25 2.5-

inch disk drives or SSDs, or up to 15 3.5-inch drives. Disk Processor Enclosures (DPEs)

contain drives, redundant dual-active intelligent RAID controllers, dual power supplies,

and dual cooling components. Disk Array Enclosures (DAEs) contain drives, switches,

power supplies, and cooling components. Up to nine DAEs can be attached to a DPE,

supporting up to 250 drives.

Overview of the Management Consoles

Edison Group developed the CMCS analysis with the premise that an efficiently

designed, intuitive GUI can reduce the time administrators spend managing storage, as

well as the time spent training and refreshing staff. It can also serve to greatly reduce the

number and length of calls to support administrative issues.

3 EMC VNX Series also supports optional SSD and associated data tiering in conjunction with the

addition of EMC FAST Suite software.


IBM Storwize V7000 Management Interface

A browser-based GUI, the IBM Storwize V7000 management interface is intuitive and

easy to navigate. The home page offers four optional views. The default view is the

Getting Started screen (Figure 1), a robust graphic interface through which you can view

the configuration status and access the means for performing specific tasks.

Figure 1: IBM V7000 Getting Started Screen

The Getting Started screen presents an object-oriented view. Click on any onscreen

object to go to management operations and/or stats displays for those items. The screen

shown here provides an excellent graphical flow chart of the system components and

the steps required to provision storage-to-host systems. This view provides an easy way

to confirm physical system resources and components, as well as a gateway to

configuring more advanced system features. The Getting Started view additionally

provides e-Learning and Information Center links that can provide detailed information

on each component in the storage provisioning process.

The Storwize V7000 management interface provides an object-oriented view of the

system components organized in column format on the left side of each display, as

shown in Figure 2 (below). This allows for easy scrolling from component to component.


Positioning the cursor over an individual object will provide drill-down options of

available administration tasks for the component depicted by the object.

Figure 2: IBM Storwize Volumes Status & Management View

In this view, the middle of the screen displays system status information for volumes

(also commonly referred to as LUNs). The bar graph to the left indicates system capacity

(used capacity in blue and total system capacity in black), and a component view is in

the middle of the display. Position the cursor over each object to display detailed system

information.

Detailed information on the drives in each enclosure can be displayed by clicking on a

disk shelf in the graphic. Clicking the link below the display presents a table of system

statistics.

Volumes in the Storwize V7000 system are virtual containers. They are abstracted from

physical disk drives (internal to the system or on external virtualized systems) via

managed disks and pools and then presented to host servers. The “Volume by Pool”

view (shown in Figure 3, below) allows the administrator to see detailed information for

each Storwize V7000 volume, including its pool association.


Figure 3: IBM Storwize Volume by Pool View

The display shown in Figure 4 (below) shows an example of the interface used in

creating a Volume, which provides options between preset defaults or the flexibility for

customized volumes with the Advanced tab.

Figure 4: IBM Storwize Creating a Thin-Provisioned Volume


EMC Unisphere

The management console for the EMC VNX Series, EMC Unisphere, runs solely on a

Windows server and allows for the monitoring and management of multiple EMC

CLARiiON, Celera, and VNX storage systems from a single console. In addition, EMC

Unisphere presents an attractive and informative monitoring dashboard as the default

view. The screenshot in 5 (below) shows a dashboard view.4

Figure 5: EMC Unisphere Dashboard

Dashboards provide a status overview for each function on the managed storage

systems. Unlike the IBM Storwize V7000 management interface, the Unisphere

dashboard offers considerable flexibility in the customization of its displays. A single

screen for at-a-glance management and reporting, the Unisphere dashboard gives you

instant and actionable knowledge about status and events across the entire storage

environment. Properly set up so that all systems have the same username and password,

Unisphere’s single sign-on can automatically discover all supported EMC installations in

the environment, including VNX, CLARiiON, Celerra, and EMC RecoverPoint SE.

4Our test environment contained one new storage system, so the amount of information

presented is limited to that system.


Unisphere includes a self-service support ecosystem that is accessible with one-click,

task-based navigation, and controls for intuitive, application context-based

management. It provides customizable dashboard views, graphics, and data tables that

present key information in the context of how you manage storage.

The display shown in Figure 6 (below) shows an example of the interface used in

creating a LUN.

Figure 6: EMC Unisphere - Create LUN Interface


Results Summary

The results of Edison’s testing (Table 1, below) show that IBM Storwize V7000

demonstrates significant advantages over EMC VNX5500 in the area of management

ease and, therefore, in administrative costs.5

Our objective findings show that, overall, managing an IBM Storwize V7000 system with

its management interface software is 47 percent less time-consuming and 31 percent less

complex over a set of common tasks than managing an EMC VNX system using

Unisphere software.

Table 1: IBM Storwize V7000 CMCS Summary of Results

IBM Storwize V7000 EMC VNX 5500

Task Time Steps Time Steps

Provisioning

Test Results for Task Category 176 8 400 14

IBM Advantage (EMC-IBM) 224 6

IBM Advantage %

(EMC-IBM/ABS(EMC)) 56% 43%

Workday Savings (IBM Advantage *

Weighting Factor) 8%

Data Protection Replication



IBM Advantage %




Maintenance and Configuration


IBM Advantage (EMC-IBM) -13 0

5 The Microsoft Excel formulas used in the calculations throughout this document are shown in

parentheses next to each title.




IBM Advantage %

(EMC-IBM/ABS(EMC)) -8% 0%


Weighting Factor) -1%

Monitoring



IBM Advantage %




Totals

Test Results Totals 506 31 950 45

Total Time Savings: IBM Advantage

(EMC-IBM) 444 14

IBM Advantage %


Average Workday Savings (IBM

Advantage % * Total Factors tested) 34%

$ Savings6 $25,686

For most IT executives, the best way to appreciate the importance of management cost

savings is by examining the findings in the context of OPEX cost savings.

The Total Time Savings in the table above is simply a sum of the savings for the tasks

evaluated. In general, Edison believes that these raw numbers do not accurately reflect

the actual workloads storage administrators’ experience (as reflected in the Average

Workday Savings), because they do not include all the tasks they perform during the

day. In order to address this, Edison developed a set of workload weighting factors that

could be applied to our testing; Edison surveyed storage administrators using storage

systems from several vendors, in organizations of all sizes.

6 Average Workday Savings x Salary derived from Table 3: Average Storage Administrator Salaries

(page 16). Results are rounded to whole dollar.


The Edison white paper, Comparative Management Cost Survey: Workload Weighting

for Mid-Range Storage Array Administrators, describes the research leading to the

identification of the weighting factors. It can be found in the Published Reports Library

on the Edison web site at http://www.theedison.com.

The factors included in this study are presented in Table 2 (below). Only those

appearing in shaded rows (i.e., 74 percent of the total workload weighting factors

identified) were factored into the evaluation for the current study.

Table 2: Storage Administrator Workload Weighting Factors

Weighting Factors 7

Provisioning 14%

Data Protection 16%

Maintenance 27%

Problem Solving 17%

Application Specific 13%

Overhead 12%

Total factors for tests

performed in this study 74%

Average Storage Admin Pay $76,333

As seen in the Average Workday Savings total in Table 1, when these weighting factors

are applied to the raw time-savings test results, IBM Storwize V7000 demonstrated a 34

percent advantage over the EMC VNX5500 system. This is examined more granularly in

the Results Details sections of this white paper.

Comparative Management Cost Savings

The Edison CMCS methodology assigns a complexity metric to task categories, as well

as measuring and comparing the time required to perform different tasks. In most real-

world business environments, management costs far outweigh licensing and vendor-

charged support costs throughout the life of the product. With this in mind, we

estimated the annual cost a business might expect save on storage administrator time

resulting from one product being easier to administer and operate than the other.

7 The weighting factors do not add up to 100 percent due to rounding.

http://www.theedison.com/pdf/2009_Samples_StorageAdmin.pdf

http://www.theedison.com/pdf/2009_Samples_StorageAdmin.pdf

http://www.theedison.com/


In order to compute cost savings, Edison used Storage Administrator salary figures

gathered from a query of salaries made at Simplyhired.com8. Edison searched for the

salaries in seven metropolitan areas of various sizes and cost-of-living. Though different

choices would affect the results, Edison believes the derived average salary is

reasonable.

Table 3: Average Storage Administrator Salaries

Storage Administrator Salaries

New York City $87,000.00

Atlanta, GA $ 73,000.00

Houston, TX $ 71,000.00

St. Louis, MO $ 69,000.00

Chicago, Il $ 76,000.00

Phoenix, AZ $ 66,000.00

Los Angeles, CA $ 69,000.00

San Francisco, CA $ 93,000.00

Seattle, WA $ 83,000.00

Average $ 76,333.00

The average of the results of this search (Table 3, above), when multiplied by the

weighted time savings, show cost savings for IBM Storwize V7000 system versus EMC

VNX5500 system:

Median Storage Administrator Salary * (Storage Administrator Time Savings) =

$76,333 * 34% = $25,686

By substituting its own costs, an organization can determine its potential savings.

Edison recognizes that these savings are not going to be realized directly. Instead, they

need to be interpreted within the context of overall storage administrator duties and

storage group or IT budgets. Within this framework, time savings of over 34 percent can

translate to reducing the need for new hires when additional storage systems are

acquired, or to enabling a better allocation of resources to mission-critical tasks.

It is not practical to attach direct financial costs to complexity. However, it should be

apparent that more complex management tools require more user training, can cause

user error simply due to that complexity, and can otherwise affect productivity.

8 This and similar queries can be performed at http://www.simplyhired.com/a/salary/home

http://www.simplyhired.com/a/salary/home


These objective differences do not tell the whole story. As is seen elsewhere in this white

paper, in most respects performing management tasks with the IBM Storwize V7000

management interface generally provides a better user experience than does EMC

Unisphere. Fewer steps and a more intuitive interface reduce the odds of user error in

execution.


Results Details

Edison compared the performance of four categories of tasks: Provisioning, Data

Protection, Maintenance, and Monitoring. Since the architecture and management

approaches of the two vendors differ, not all the tasks that comprise a tested category

could be compared. Where no equivalent function or task existed for both platforms, the

time and complexity rating results were not included in the summarized results.

Similarly, some tasks, such as replacing a disk, could not be performed for all of the

platforms as the test systems lacked sufficient additional disks.

The following sections each contain a description of the task categories, a summary of

test results for that category, a listing of the tasks performed and compared, and a

subjective appraisal of the user experience.

Provisioning

For purposes of this study, provisioning covers tasks performed after the storage system

has been installed and initialized. Installation-related tasks were not included for two

main reasons: first, a system is only installed once; second, for many organizations,

installation is performed by vendor technicians. There are organizations where storage

systems are being added to the data center daily but, in such cases, the installation teams

are generally vendor-provided technicians or staff dedicated to that task.

The tasks evaluated here include those related to preparing connectivity and the storage

devices for use by hosts. The following table (Table 4: Provisioning Tasks Comparison,

page 20) shows the specific provisioning tasks, using nomenclature for each vendor that

Edison evaluated.

Provisioning Tasks and Summary

The tasks evaluated for the respective systems were as follows:

IBM Storwize V7000 System

Configure Physical Storage (Internal Storage - Default RAID 5) — Internal storage

is the RAID-protected storage that is directly attached to the Storwize V7000 system.

The Storwize V7000 system automatically detects the drives that are attached to it.

These are configured into RAID arrays, presented as MDisks, which can be added to

storage pools in the same way as MDisks that are discovered when external storage

systems are added.


Create New Volume (LUN) — A volume is a logical disk that the system presents to

the hosts. Volumes can be Generic, Thin, Mirrored, or Thin Mirrored.

Add/Create Hosts — A host system is a computer that is connected to Storwize

V7000 through a Fibre Channel interface (IP network is also an option).

Assign/Map Volumes to Hosts — Host mapping is the process of controlling which

hosts have access to specific volumes within the system.

Search for Volumes —Previously configured hosts can be mapped to previously

configured volumes that are found.

EMC VNX5500 System

Create Storage Pools (Default RAID 5) – A storage pool is a set of disks all with the

same redundancy (RAID 5, RAID 6, or RAID 1/0), on which you create one or more

thin or non-thin LUNs.

Create LUN – (RAID 5 default, thin or non-thin).

Create/Add Hosts.

Creating Storage Groups – A storage group is a logical grouping of LUNs and hosts.

that enables managing both as a single unit.

Host Assignment to Storage Group.

LUN Assignment to Storage Group.

Search for LUNs.

The Summary of Results for Provisioning in Table 4 (below) shows that, for the

compared tasks, the IBM Storwize V7000 system was 56 percent less time-consuming

and 43 percent less complex to manage than the EMC VNX5500.

Table 4: Provisioning Summary of Results



Provisioning


IBM Advantage (EMC - IBM) 224 6

IBM Advantage %


Workday Savings

(Difference* Weighting Factor) 8%


When the weighting factor is applied, the advantages are smaller, but can be

cumulatively significant when these activities are urgent.

The two charts below illustrate the differences in provisioning time and complexity for

the two platforms.

Figure 7: Provisioning: Time and Complexity Comparisons


Data Protection

Without good data protection capabilities, there is almost no reason to invest in a

storage system. Data protection includes such features as multiple controllers, multiple

I/O paths, remote replication, and the creation of snapshots and copies. Multiple

controllers and I/O paths are dependent upon the physical attributes of the appliance

and are generally configured as part of installation. This study does not include an

evaluation of the management of the physical controllers and I/O paths. Remote

replication was not tested because the Edison lab only had one system from each

vendor. That leaves the creation of copies and snapshots. 9

A copy 10 is defined essentially the same way on either platform — an exact replica of

existing data on the system managed in the same manner as the source data. Copies can

be used as a backup, especially when replicated to a second local or remote storage

system. This approach, typically used to enable high availability, usually takes the form

of what EMC terms a mirror and IBM calls a mirrored pair, meaning that the data in

each copy is regularly updated and synchronized through replication. Copies can be

made to retain a relationship with the original data, or not. Copies are also often used in

development environments where it is desirable for developers to work with real data,

but where using live data would be too risky to allow.

A snapshot creates a point-in-time view of the original data. The snapshot is not

intended to be an independent copy but is used to maintain a view of the original data at

the time the snapshot is created. Therefore, the snapshot holds only the data from

regions of the original volume that have changed subsequent to the creation of the

snapshot (starting with no data at all). Since the snapshot uses thin provisioning, only

the capacity required for the changes is used. Compared to full copies, snapshots require

much less additional storage space on an array — typically 10 to 20 percent of the

original size, rather than the 100 percent capacity required by a copy.

On the EMC product, snapshots are created at the LUN or Vdisk level. For EMC, each

LUN can have its own snapshot policies, easily matching the business needs.

9 For in-depth descriptions and explanations of these functionalities in IBM Storwize V7000, documentation

can be accessed at:

http://publib.boulder.ibm.com/infocenter/storwize/ic/index.jsp?topic=%2Fcom.ibm.storwize.V7000.doc%2F

mlt_relatedinfo_224agr.html 10 Often referred to as a clone; though to avoid confusion between product nomenclature, “copy” is used

except in explicitly defined instances.

http://publib.boulder.ibm.com/infocenter/storwize/ic/index.jsp?topic=%2Fcom.ibm.storwize.v7000.doc%2Fmlt_relatedinfo_224agr.html

http://publib.boulder.ibm.com/infocenter/storwize/ic/index.jsp?topic=%2Fcom.ibm.storwize.v7000.doc%2Fmlt_relatedinfo_224agr.html


On the IBM product, snapshots are accomplished using a FlashCopy snapshot preset

function that creates a point-in-time view of the production data.

Data Protection Tasks and Summary



Create Snapshot

Create Copy

Flash Copy Mappings – equivalent to Snap Mirror – maps snapshot to source for

updating

Start Snap

Restore Snap/Copy

EMC VNX 5500 Systems

Create Reserved LUN Pool – to hold snapshots

Creating a Snapshot (SnapView) – sets the parameters for the snapshot

Start Snapshot Session – this creates the snapshot

Add a Snapshot to Storage Group

Activate and Deactivate Snapshots – making it available (or unavailable) to a host (in

a Storage Group)

Restoring Snapshot Copies

Configure Clone (Copy) Settings

Creating Snap Clone (Copy)/Mirror

Consistency groups are a notable time-saver in the typical scenario, where applications

are associated with multiple LUNs/volumes. Enabling a single, consistent point-in-time

copy across multiple volumes, consistency groups are important in scenarios such as a

database environment, where obtaining a consistent copy would require a temporary

suspension of database operations. Consistency groups allow administrators to group

multiple volumes, after which they can create a copy of, or restore, particular groups

instead of individual volumes. For example, standard practice with SQL Server would

be to have a volume in the Storwize V7000 storage system for data, and logs stored on

another volume in order to keep them (and possibly configure them) separately. You can


combine them into a “SQL Server Consistency Group” and snapshot or copy them as a

single entity for such purposes as recovery or development.

As can be seen in Table 5 below, when the IBM system is compared to the EMC system,

it is 66 percent less time-consuming and 40 percent less complex to manage.

Table 5: Data Protection Summary of Results



Data Protection Replication


IBM Advantage (IBM - EMC) 198 6

IBM Advantage %


Workday Savings


The two charts below show the differences more dramatically by providing a visual

indication of differences in data protection time and complexity for the two platforms.


Figure 8: Data Protection: Time and Complexity Comparison

Maintenance and Configuration Changes

Maintaining a storage system includes a wide range of activities, including software

updates, replacement of failed drives, and so forth. Configuration changes include

additional capacity realized by adding drive shelves and drives, changing usage

configurations, and the deletion of snapshots and copies for which there is no further

use.

The Maintenance and Configuration Changes tasks evaluated in this study consist of

such activities as deleting outdated snapshots, managing and expanding LUNs,

destroying inactive LUNs, and reconfiguring or decommissioning storage pools or

aggregates. Other tasks that fit under the topic but that were not evaluated include

removing and replacing failed drives, adding additional drives, and so forth.

Maintenance and Configuration Changes Tasks and Summary




Expand Storage Pool

Delete Storage Pool

Expand Volumes

Delete Volumes

Delete Snapshots

Delete Copies

Search Volumes

Delete Host

EMC VNX5500 System

Expand Storage Pool

Expand LUNs

Destroying LUNs

Destroying RAID Groups/Storage Pool

Destroying/Deactivating Snapshots

Destroying Clones (Copies)

Deleting Host

Performing tasks may require additional prior tasks. For example, destroying a clone

(copy) that is attached to a host requires that it be detached from the host or taken offline

before it can be destroyed. The number of different possible scenarios would, if

included, add unnecessary complexity to this analysis.

The results in Table 6 (below) show that performing these tasks with Unisphere is 8

percent faster than performing the equivalent tasks with the IBM Storwize V7000

management interface. A comparison of the individual tasks reveals that the time

difference was due to two factors. First, an additional task, Search LUNS/Volumes was

performed on the V7000 that was not tested on the VNX – this added 12 seconds to the

total. Second, the time required to expand the storage pool was longer on Storwize

V7000 than on the VNX. The resulting 8 percent advantage for VNX is significant, in

itself, but when weighting is applied, the resulting 1 percent difference is insignificant.


No appreciable difference in complexity was found between the two management

interfaces for these tasks.

Table 6: Maintenance and Configuration Changes: Summary of Results



Maintenance and Configuration


IBM Advantage (IBM - EMC) -13 0

IBM Advantage %

(EMC-IBM/ABS(EMC)) -8% 0%

Workday Savings

(Difference* Weighting Factor) -1%

The following two charts provide a graphic illustration of the performance differences.


Figure 9: Maintenance and Configuration Changes Comparison

Monitoring

During the interviews Edison conducted when developing the workload weighting

factors, many of the respondents mentioned that their most important activity was

monitoring system status. By its nature, monitoring does not require significant effort,

but properly configuring monitoring tools both enables timely preventive maintenance

and simplifies troubleshooting. Performing troubleshooting tasks most often occur

outside of the management interfaces, so were not included in this study.

For this study, Edison only compared the management tools provided in the two

management consoles, IBM Storwize V7000 and Unisphere. Monitoring tools that

required the use of external software were not included. In addition, since monitoring is

a passive process by definition, we did not evaluate the use of the monitoring tools

themselves.

Therefore, we compared only the configuration of monitoring on the two systems. The

tasks evaluated for the respective systems were as follows:



Configure Event Notifications – E-mail

Configuring Event Monitoring – SNMP/Syslog

Remote Support/Dial Home

EMC VNX5500 System

Configuring EMC Event Monitoring – E-mail

Configuring EMC Event Monitoring – SNMP

Configuring Host Notification

Configuring Remote Support

It is important to note that though Edison performed all the tasks for both platforms, not

all of the tasks were performed separately on each. For example, with Unisphere, all of

the monitoring configuration tasks are performed without using additional utilities.

Table 7: Monitoring: Summary of Results



Monitoring


IBM Advantage (IBM - EMC) 35 2

IBM Advantage %

(IBM-EMC/ABS(IBM)) 39% 50%

Workday Savings


The effect of task consolidation is evident in the results in Table 7 (above). Even though

there is only one interface required for configuring monitoring on VNX versus two on

V7000 (there is a separate interface for configuring remote support), there were twice as

many steps required to perform the same activity on VNX and the time difference, near

40 percent, is quite large.


Figure 8: Monitoring Comparison


Though troubleshooting tasks were not evaluated for this study, the IBM Storwize

V7000 management interface has a wizard-based troubleshooting aid, Recommended

Actions, which deserves mention, since it can reduce demands on an administrator’s

time. Clicking Recommended Actions in the Troubleshooting popup brings up a

context-sensitive display appropriate to the detected problem. Selecting an error code or

message and clicking on “Run the Fix Procedure” will bring you though the steps

involved in addressing the problem, as shown in the example below (Figure 10).

Figure 10: IBM Storwize V7000 Recommended Actions Display

The Recommended Action feature can save administrators from having to search

through the Help screen knowledge base to determine how to diagnose and remedy the

problem.


Methodology for This Study

Edison deployed storage systems from IBM and EMC in a lab within its New York City

facility, and then performed a series of management tasks, capturing the steps and time

required using the Edison Comparative Management Costs Study methodology. Details

about the methodology, as well as the lab configuration and the testing process, are

described below.

CMCS Methodology

The CMCS methodology was created by Edison to be able to objectively compare the

manageability ease-of-use for enterprise technology products. Edison devised the

methodology to provide an objective metric for comparing Information Technology

management platforms. More subjective metrics, such as those derived from interviews

with groups of testers in typical user-experience testing, are excellent for understanding

the testers’ preferences at the time of testing, but results vary significantly for different

groups of testers and test conditions.

Objective metrics based on mouse clicks cannot adequately address issues such as the

difference between Wizard-based versus non-Wizard based interfaces. The Edison

methodology attempts to address these concerns by establishing a set of rules that can

account for complexity and different interface design philosophies. A full description of

the methodology can be found in the appendix of this report.

Laboratory Configuration

Edison's test lab was configured with systems from IBM and EMC. On the following

page, Table 8 lists the storage system models, hardware features, and the licensed

software installed in the lab.


Table 8: Lab Configuration

VNX5500

Hardware

Model EMC VNX5500

Storage Processor Dual Processor (SPA & SPB)

Memory Per Processor 12288 MB

Revision/Flare Code 5.31.0.5.502

Storage

Disk Array Enclosure 0 – 24 Disks (Includes two Hot spares)

1 – 24 Disks (Includes two Hot spares)

Disk Type 300 GB SAS

RAID Configuration RAID 5

Storage Capacity Physical Capacity 14.4TB Raw, minus EMC VNX OS

Vault space

Licensed Software

EMC Unisphere File & Block (Navisphere license included.

Unisphere replaces Navisphere at installation).

SnapView, SAN Copy

IBM Storwize V7000

Hardware

Model Storwize V7000

Revision 6.2.0.3

Memory per Processor 8000 MB

Storage

Drive Enclosure 1 – 24 Disks

2 – 24 Disks

Disk Type 300 GB 10K SAS

Storage Physical Capacity 14.4 TB Raw

Licensed Software

Storwize Management Software

Copy Services – Flash Copy & Remote Copy


Test Procedures

This study focuses on regularly performed administrator tasks. Edison divided the tasks

into categories that relate to the tasks typically performed by storage administrators on a

daily basis: 11

Provisioning – Provisioning includes all the tasks or operations performed after

installation in order to attach an array to servers and store data. These include global

tasks such as creating a storage pool, configuring ports for connectivity to hosts, and

the creation LUNs or volumes so the array can actually be put to use.12

Data Protection – Data protection covers such features as the creation of snapshots

and copies.

Maintenance and Configuration Changes – Maintenance and Configuration

Changes include performing maintenance tasks such as adding additional capacity,

cleaning up unneeded snapshots, copies, and so forth.11

Monitoring and Troubleshooting – Monitoring an array consists of identifying

performance and operational parameters that affect uptime and performance, setting

alerts, and generating reports on status and system condition. Troubleshooting

consists of identifying the causes of issues identified through monitoring, or from

other sources, such as server administrators or end users concerned about

performance or data availability. Only enabling and configuration of monitoring

were evaluated in this study.

Overhead or Other – These tasks include such tasks as budget or planning meetings,

training, and other activities not directly related to any specific storage array. These

activities were not evaluated in this study.

Edison identified tasks under each category and matched them between the platforms

compared in this study. Since the vendors use either different nomenclature for the same

feature or the same nomenclature for different features, this was a very important first

step.12

Administrators rarely perform specific tasks in isolation. Often, the administrator has a

goal that requires the performance of a combination of several tasks or operations. To

11 The tasks listed for the categories are illustrative, not inclusive. Not all of the tasks listed were

evaluated nor are all possible tasks for a category listed. In addition, these categories are not

exclusive: tasks listed for one category may be justifiably perceived as belonging to a different

category. 12 See the appendix for a table comparing the equivalent nomenclature for the features and

functionality used by each of the vendors.


emulate this approach, Edison further categorized the task list to reflect a goal-oriented

approach. This also simplified comparisons where the architectural differences between

the two platforms would make task-to-task comparisons difficult or even impossible.

Table 9 (below) shows the list of tasks and goals, organized by category.

Table 9: Task Categories

Provisioning

Baseline Provisioning Tasks that need to be performed prior to creating usable storage

on any storage system.

Preparing Storage This series of tasks includes the creation of a storage pool from

the drives in the system.

Preparing

Connectivity

For this study, this series of tasks includes all the operations

required for setting up access to FC Hosts on the system.

Configuration of other network protocols was not evaluated in

this study.

Configuring Usable

Storage

This category includes the creation of storage objects that can be

attached to a host or server.

Data Protection

Creating Snapshots These tasks include the creation and scheduling of snapshots.

Creating Clones

(Copies) These tasks include the creation of clones.

Replication These are tasks related to replicating data onto remote storage

systems. Replication tasks were not performed during this study.

Maintenance and Configuration Changes

Removal of Unused

Storage Objects

This includes the deletion of old snapshots or clones, deletion of

LUNs, etc.

Monitoring and Troubleshooting

Monitoring and

Troubleshooting

This includes the performance of a series of tasks related to the

identification of problems on the systems. For this study, the

comparison focuses on the configuration of monitoring tools.

GUI vs. CLI

Edison believes that well designed GUIs can greatly improve the quality of system

management, compared to the exclusive use of a command line interface (CLI) or

scripting. This is especially true for the less skilled staff usually tasked with day-to-day

management.


Getting the Best of Both Approaches

As stated in the accompanying subsection, the

ideal GUI is one that generates CLI commands

to reflect the actions implemented using the

GUI. This feature is part of the IBM Storwize

V7000 management interface. It is a useful

way for administrators to learn the various

CLI commands. Additionally, the commands

generated by GUI actions may be copied and

pasted into a text editor in order to create

scripts that can then be executed by the

system. In this manner, an administrator can

programmatically automate frequently used

actions. Doing so could result in still further

reducing the time and steps involved in using

the IBM Storwize V7000 system over other

storage systems.

An example of this can be seen in creating

LUNs. In EMC Unisphere the Create LUN

dialog box (Figure 5, page 10), creating

multiple LUNs is simply a matter of entering

the number to be created in the “Number of

LUNs to Create” field. The IBM Storwize

V7000 management interface lacks an

equivalent field; though multiple volumes can

be created within the “New Volume” dialog

box, each instance needs to be added

manually. However, if creating volumes is

done on a frequent basis, a script can be

created using CLI commands generated by the

GUI, which can be used to create a specific

number of volumes with a single action.

Edison does not oppose the use of the CLI or scripts, but we believe that for the majority

of day-to-day tasks, a GUI can lower training and task-oriented support costs and

prevent operator error (both significant factors in administrative efficiency) and thus,

cost. In fact, a good GUI should streamline the use of scripts by providing an interface

for running and creating scripts through learning or similar capabilities. By enabling the

use of scripts for the performance of repetitive tasks while providing access through a

GUI, the best features of both approaches can be utilized.

Dick Benton, principle consultant at

GlassHouse Technologies, Inc., wrote an

article on storage staffing published by

SearchStorage. The theme of the article is

that a traditional measure of storage

administrator staffing needs — Terabytes

per Full-Time Employee — is almost

meaningless. This is because the metric can

only be calculated within the context of each

individual organization. As a practical

matter, TB/FTE can only be used after

acquisition and implementation, and then

only for analysis of staffing requirements for

future expansion of the existing

infrastructure. Changing the infrastructure

to a different platform changes the basis for

TB/FTE calculations.

The article lists three things to consider

when calculating storage management

staffing requirements. The first factor is

called “technology factors”, which are the

technologies (hardware and software) that

require significant training or experience for

use. The other two factors, “transaction

factors” (the day-to-day tasks performed by

storage administrators) and “complexity

factors” (“factors that impact a storage

administrator's need for skills and the time

needed to execute a task”) have a major

influence on the technology factor. The

easier a technology is to use, the less training or experience is required for its use. Edison

employs these same criteria in comparing storage administrator costs in this study.

http://searchstorage.techtarget.com/tip/0,289483,sid5_gci1250274,00.html?bucket=ETA&topic=306649%3e

http://searchstorage.techtarget.com/


Other Considerations

As mentioned above, this study only considers the effect of greater administrative

efficiency on ownership costs. Other factors, such as acquisition costs, space and power

utilization, third-party installation, decommissioning, and so forth are not included.

There is one other ownership cost factor that is not being directly analyzed but which

has a bearing on this study: the importance and nature of planning in implementing

complex IT infrastructures.

Planning for a SAN implementation requires an analysis not only of how much storage

is required (including projected expansion), but also the nature of what is being stored.

Such considerations include the existence of Microsoft Exchange, SQL Server, or Oracle

databases, how much capacity they require, and what data protection policies are

needed for operational and regulatory reasons. At a minimum, SAN planning requires

the identification of the hosts to be attached to the system, operating systems and

application data to be stored, and any data retention and protection policies in place.

Installing any of the systems Edison evaluated requires these minimum planning steps.

In the modern organization, there is one constant for storage utilization: the storage

capacity required, and the hosts and applications to which it is attached, will change

rapidly and often in unanticipated ways. If a storage system offers insufficient flexibility

to accommodate the rapidly changing environment into which it is placed, the costs of

administration can grow very quickly. A system that requires adherence to an overly

structured planning process and storage schema can prove very difficult to adapt to

changing circumstances. A highly flexible system will enable rapid IT responsiveness to

business changes and lower the costs accrued from those changes.

How to Use These Results

White papers such as this one are intended to help readers make product acquisition

decisions. For midmarket storage arrays, the purchase decision must include many

factors. Mid-size organizations often have relatively smaller IT organizations, with

administrators wearing many hats. The more efficient the administrator’s toolset, the

more productive the administrative staff can be.

When reviewing these results, consider the organization’s file storage and application

integration requirements. Review staffing policies as well, including training programs

and other factors. Also, evaluate the skill levels of existing staff. If the team has great

skills and deep knowledge of storage management issues, the choice of storage system

management tools may seem moot; but a more efficient platform can enable teams to

make better use of their time.


Conclusions

The inevitable increase in storage capacity requirements, along with other factors

(including the continued adoption of server virtualization), drives organizations to

acquire additional storage systems or to expand the systems they have. The ongoing

capital expenditure costs are not going away in the foreseeable future. Therefore,

organizations seeking to control costs must look at the OPEX costs associated with

managing their ever-growing storage hardware deployments.

The IBM Storwize V7000 management interface delivers a compelling savings in OPEX

through its highly efficient management capabilities. Edison testing has shown savings

of over 47 percent in administrator time and 31 percent less complexity versus

performing the same set of tasks with EMC Unisphere.

If workload-weighting factors are applied to these results, the savings can be monetized

in average administrator time savings of more than $25,000 per year (34 percent of an

administrator’s time) with the IBM Storwize V7000 management interface over EMC

Unisphere.

Edison believes that, for organizations in need of a mature, stable storage platform for

mid-range enterprise applications, the IBM Storwize V7000 management interface

provides a superior combination of capabilities at a lower OPEX cost than does the EMC

VNX5500.


Appendices

Appendix I - CMCS Methodology Description

The Methodology Defined

Edison Comparative Manageability Cost Studies methodology is a product

manageability cost-evaluation process. Products in question are compared against a set

of task-oriented objective and subjective metrics in order to derive an accurate set of

analytical results. The outcome of this study determines the Comparative Management

Cost (CMC) incurred by managing and operating the products in a production

environment. The methodology employed to conduct this comparison consists of the

following elements:

The Study

The study is the baseline checklist of standard administration tasks performed routinely,

compared quantitatively and qualitatively to determine, on a task-by-task basis, which

product is superior, primarily in terms of ease of administration. Certain tasks are also

measured in terms of system speed-of-execution — the wall-clock time it takes for the

system to complete a job once it has been submitted by an administrator. The function of

this study is to derive a meaningful set of CMCS statistics that can reveal the real

difference in management costs for the products in question. To do this, CMCS is used

to apply a set of quantitative metrics, developed by Edison Group, to a list of tasks

typically regarded as qualitative in nature.

Tasks

Edison defines a task as a complete logical activity, composed of one or more steps,

which together significantly alter the state of the device or software program that

accomplishes a specific work goal. Each task is measured for time and complexity. Time

and complexity, as used in the study, are defined as follows:

Time

The amount of time it takes to perform a given task. For asynchronous tasks, where a job

can be run in the background while the administrator is accomplishing other things,

time is measured strictly in terms of how long it takes the administrator to perform the

steps to configure, initiate, and submit a given task.


Other (synchronous) tasks in the study demand the administrator’s full attention and

prevent the accomplishment of other tasks (as in performing a hot recovery operation on

a live database). In that case, time includes both the time it takes for an administrator to

configure/execute the task in question and the time it takes the system to complete the

task. All time metrics are measured in wall-clock time.

Complexity

Complexity is measured using a proprietary metric devised by Edison Group: the

number of system-affecting steps it takes to complete a given task. A step is defined as a

task component that effects a change of state to the system under test.

Because not all steps have the same inherent complexity, each step is further broken

down into increments to account for the difference. An increment is a decision point that

the user must make to complete a step. Increments are technically defined as a part of a

step that will have a measurable effect on the state or execution path, but which does not

itself affect a change upon the underlying system state until the step is complete. For

example, selecting Basic vs. Advanced Install with the installation wizard is an

increment, not a step.

Complexity is then measured in terms of number of steps, but taking into account

the following factors:

The number of increments it takes to complete each step.

Whether or not instrumentation for a given step is GUI-based or requires the use

of a command line/scripting interface.

Whether or not the task requires a context switch between multiple interfaces in

order to be completed. If a context switch exists, then additional steps will be

added to the total step-count for a given task.

The above factors affect the complexity calculation as follows:

The primary measure is steps. If a step has many increments, it is considered several

steps. The metric allows each step five increments, and we add steps for each additional

five increments, rounded up. So if a step has between zero and five increments, it

remains unchanged; if it has between six and 10 increments, it is increased by one;

between 11 and 15 increments, it is increased by two, and so on. We decided to do this

because, while increments are secondary to steps in determining complexity, they do

modify the relative complexity of a given step in the course of completing a task. In

other words, steps with a low number of increments are simple, and steps with a high

number of increments are complex.


The other modifiers (instrumentation and context switching) may occur very

infrequently in the products under review. Still they are significant enough factors that

we needed to account for them in some meaningful way to generate a measure of

complexity that accurately reflects our experience of using the products.

Regarding instrumentation, if an operation could be executed entirely within a GUI

interface, then the complexity/step value for that task would remain unmodified. If, on

the other hand, a step required the use of a command line interface, this would increase

the step count. For a simple single-line command operation, the step count was

increased by one. Where the operation required the user to write a script, the step value

was increased by two or more, depending on how much work was required to write the

script in question.

Lastly, we come to the matter of context switching. If a context switch was encountered

during the course of completing a given task, then two or more steps were added to the

step count for that task. The possible addition of more than two steps was allowed for as

a judgment call on the part of the subject-matter expert performing the task under

consideration. We regard tasks containing context switches, which require

understanding the dependencies of relating and performing a single operation in two

different environments, as inherently more complex than performing a similar task

when operations can be accomplished in one place.

The following is the complexity formula utilized throughout these studies.

Complexity Calculation Formula

Complexity is defined as the number of computed steps it takes to complete a given

task. The formula Edison typically uses to compute complexity for each of the tasks in

this study is as follows:

For every five increments contained in a step, we increase the step value by one. For

example:

If a step has 0–5 increments, step value = step + 0,

If a step has 6–10 increments, step value = step + 1

If a steps has 11–15 increments, step value = step + 2

… and so on.

The type of instrumentation offered to perform a given task modifies the task’s

complexity.

If a task can be performed completely with a GUI, then step count = step count + 0.


If a task requires the use of a command line interface, then step count is modified as

follows:

If the command line operation consists of a single-line command, then step count = step

count + 1.

If the command line operation requires writing a script, then step count = step count + 2

or more steps, depending on a subjective assessment of the complexity of the script.

If a task requires a context switch between different environments, then step count =

step count + 2 or more steps, depending on a subjective assessment of the complexity of

the context switch.


Appendix II - Terminology Glossary

This table lists the equivalent feature nomenclature for the operations and tasks

evaluated in this white paper. The list covers the two vendors with a brief description of

the core functionality and descriptions for each vendor’s implementation of that

functionality. The cell will be blank if the vendor lacks an equivalent feature.

IBM Storwize V7000 EMC VNX5500 Description

Physical Storage

Physical storage is used to

configure and manage

storage pools, internal

and external storage, and

MDisks, and to migrate

existing storage to the

system.

Internal Storage

Internal storage is the

RAID-protected storage

that is directly attached to

the Storwize V7000

system.

Storage Pool

A storage pool is a

collection of MDisks that

jointly contain all of the

data for a specified set of

volumes.

Storage Pool

A storage pool is a means

of storage allocation from

any type of disk and can

incorporate multiple tiers

(Flash, FC, and SATA) in

the same pool. Storage

pools are defined by an

administrator before the

creation of any LUNs.

LUNs can be created at

pool level; these pool

LUNs are no longer bound

to a single storage tier and

can be spread to different

storage tiers within the

same pool.

Some or all of disks in a

system, collected into a

unit of or for virtual

space. (The characteristics

of such collections vary

with vendor).

MDisks

A managed disk (MDisk)

is a logical unit of

physical storage. MDisks

are either arrays (RAID)

from internal storage, or

volumes from external

storage systems. MDisks

are not visible to host

systems.

RAID Groups

A RAID group is a type of

storage pool. It is a set of

disks with a RAID type on

which you create one or

more LUNs with the same

RAID type. The LUN is

distributed equally across

all the disks in the RAID

group.

RAID group is the actual

container for data

protection, where

multiple LUNS or

volumes are created and

assigned to a host.



Volume

A volume is a logical disk

that the system presents

to the hosts. MDisks in a

pool are split into

"extents" of the same size.

Volumes are created from

the extents that are

available in the pool.

There are three types of

volumes: striped,

sequential, and image.

Application servers on

the SAN access volumes,

not MDisks or drives. To

keep a volume accessible

even when an MDisk on

which it depends has

become unavailable, a

mirrored copy can be

added to a selected

volume. Each volume can

have a maximum of two

copies. Each volume copy

is created from a set of

extents in a storage pool.

LUN

A logical unit number

(LUN) is a unique

identifier used to designate

individual or collections of

disk devices for address by

a protocol associated with

a SCSI, iSCSI, Fibre

Channel (FC), or similar

interface.

LUN or volume is a

logical disk created from a

storage pool and assigned

to host. A LUN could

reference an entire RAID

set, a single hard disk, or

multiple disks.



Thin Provisioned

Volumes

When you create a

volume, you can

designate it as thin-

provisioned. A thin-

provisioned volume has a

virtual capacity plus a

real capacity.

Virtual capacity is the

volume storage capacity

that is available to a host.

Real capacity is the

storage capacity that is

allocated to a volume

copy from a storage pool.

In a fully allocated

volume, the virtual

capacity and real capacity

are the same. In a thin-

provisioned volume,

however, the virtual

capacity can be much

larger than the real

capacity.

Thin LUN

A pool LUN with a thin

property. A thin LUN is

able to have a subscribed

user capacity that is

greater than the user

capacity of the shared

pool.

Virtual provisioning/thin

provisioning is a strategy

for efficiently managing

space in a storage area

network (SAN) by

allocating physical

storage on an "as needed"

basis.

This strategy gives a host,

application, or file system

the illusion that it has

more storage than is

physically provided.

Physical storage is

allocated only when the

data is written, rather

than when the application

is initially configured.



FlashCopy

FlashCopy software lets

you make an instant,

point-in-time copy from a

source volume to a target

volume. Without it, if the

data set changes during

the copy operation, the

resulting copy might

contain data that is not

consistent. More

advanced FlashCopy

functions allow

operations to occur on

multiple source and

target volumes.

FlashCopy management

operations are

coordinated to provide a

common, single point-in-

time for copying target

volumes from their

respective source

volumes. This creates a

consistent copy of data

that spans multiple

volumes. The FlashCopy

function also allows

multiple target volumes

to be copied from each

source volume. This can

be used to create images

from different points in

time for each source.

Rollback/Restore

Snapshot or Clones

If the rollback is performed

while a snapshot is still

active to this session, the

snapshot writes will be

copied to the source LUN.

If the snapshot is

deactivated, the original

session data will be copied

to the source LUN.

Snap View

SnapView software lets

you create local point-in-

time snapshots and

complete data copies

(clones) for testing,

backup, and recovery

operations.

Snapshots/Copies are part

of data protection, used in

creating an instant, point-

in-time copy of the source

volumes or LUNS.

It is difficult to make a

consistent copy of a data

set that is constantly

updated; point-in-time

copy techniques help

solve this problem.



Snapshot

The snapshot preset

creates a point-in-time

view of the production

data. A snapshot is not

intended to be an

independent copy, but is

used to maintain a view of

the production data at the

time that the snapshot is

created. Therefore, the

snapshot holds only the

data from regions of the

production volume that

have changed since the

snapshot was created.

Clone

The clone preset creates an

exact replica of the

volume, which can be

changed without

impacting the original

volume. After the copy

operation completes, the

mapping that was created

by the preset is

automatically deleted.

Backup

The backup preset creates

a point-in-time replica of

the production data. After

the copy operation

completes, the backup

view can be refreshed

from production data with

minimal copying of data

from the production

volume to backup volume.

SnapView Snapshot

The defined virtual device

that is presented to a host

and enables visibility into

running sessions. The

snapshot will be defined

under a source LUN in

such a way that activation

of that snapshot will only

be allowed on any running

sessions belonging to that

same source LUN. A

snapshot can only be

assigned to a single

session; thus, to have two

active snapshots for the

same source LUN, you

must have two separate

sessions running in which

to activate two separate

snapshots. Active

snapshots are fully read

and write-capable. Once

the snapshot is

deactivated, however, all

writes to the snapshot will

be deleted.

SnapView Clone

Snap View clones are fully

populated point-in-time

copies of LUNs that allow

incremental

synchronization between

source and destination

LUNs.



Reserved LUN Pool

Collection of LUNs used to

support the pointer-based

design of SnapView. As

the first SnapView session

is started on a given source

LUN, a reserved LUN is

assigned to the source

LUN. If a SnapView

session runs long enough

for the assigned reserved

LUN to be filled, the next

available LUN in the

reserved LUN pool will be

assigned to the source

LUN. Reserved LUNs are

thus assigned on a per-

source-LUN basis, such

that source LUNs have a

one-to-many relationship

to their reserved LUNs.

Server writes made to an

activated snapshot are also

stored on a reserved LUN

in the global reserved LUN

pool. When you deactivate

the snapshot, the reserved

LUN space is freed and all

snapshot writes are

destroyed.



FlashCopy Mappings

A FlashCopy mapping

defines the relationship

between a source volume

and a target volume.

The FlashCopy feature

makes an instant copy of a

volume at the time that it

is started. To create an

instant copy of a volume,

one must first create a

mapping between the

source volume (the disk

that is copied) and the

target volume (the disk

that receives the copy).

The source and target

volumes must be of equal

size.

SnapView Session

This is the process of

defining the point-in-time

designation by invoking

copy-on-first-write activity

for updates to the source

LUN. Starting a session

assigns a reserved LUN to

the source LUN if no other

sessions are running on

this same source LUN.

Note that as far as this

session is concerned, until

a snapshot is activated, the

point-in-time copy is not

visible to any servers.

However, we are tracking

the source LUN so we can,

at any time in the future,

activate a snapshot to this

session in order to present

the point-in-time image

(when the SnapView

session was started) to a

host. As noted earlier, each

source LUN can have up to

eight sessions.



FlashCopy Consistency

Groups

A consistency group is a

container for mappings.

Many mappings can be

added to a consistency

group. Enabling a single,

consistent point-in-time

copy across multiple

volumes, consistency

groups are important in

scenarios, such as a

database environment,

where obtaining a

consistent copy would

require a temporary

suspension of database

operations.

The consistency group is

specified when the

mapping is created. The

consistency group can

also be changed later.

When using a consistency

group, prepare and start

that group instead of the

individual mappings.

This process ensures that

a consistent copy is made

of all the source volumes.

Mappings to control at an

individual level are

known as stand-alone

mappings.

Storage Group

A storage group is a logical

grouping of hosts and

LUNS. The Storage Group

option lets you place LUNs

and hosts into a group so

that the designated LUNs

are accessible only to the

particular hosts included

in the storage group.



Remote Replication

The Metro Mirror and

Global Mirror Copy

Services features enable

IT administrators to set

up a relationship between

two volumes, so that

updates that are made by

an application to one

volume are mirrored on

the other volume. The

volumes can be in the

same system (usually

only for testing purposes)

or on two different

systems (usually at

different physical

locations).

RecoverPoint is a single

solution that provides

host-based and array-

based solutions while

replicating data from any

SAN-based array to any

other SAN-based array

over existing Fibre

Channel or IP network. It

provides the ability to go

back in time and recover

data in a consistent state. It

provides support for

heterogeneous storage,

hosts, networks, and

SANs.

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