2011ks pahari-san copy data migration a complete experience

8/12/2019 2011KS Pahari-SAN Copy Data Migration a Complete Experience

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SAN Copy Data Migration:

A Complete Experience

EMC Proven Professional Knowledge Sharing 2012

Dinesh Pahari

EMC Senior Engineer

Dimension Data Australia Pty Ltd

[email protected]


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ContentsPreface ...................................................................................................................................... 3

Introduction ................................................................................................................................ 4

Basic Requirements ................................................................................................................... 4

Zoning Requirements ............................................................................................................. 5

Allocate Destination LUN ........................................................................................................ 6

Create SAN Copy Connection ................................................................................................ 7

Create SAN Copy Sessions .................................................................................................... 8

Host Preparation ...................................................................................................................10

Start the SAN Copy Sessions ................................................................................................11

Monitoring the SAN Copy Session .........................................................................................12

Completing the SAN Copy Session .......................................................................................12

Terminology ..............................................................................................................................15

References ...............................................................................................................................15

Appendix ...................................................................................................................................15

Disclaimer: The views, processes or methodologies published in this article are those of the

author. They do not necessarily reflect EMC Corporations views, processes, or methodologies.


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Preface

EMC is a market leader in developing tools that simplify a SAN administrators lifeat work. Due

to the dynamic nature of IT environments, it is imperative that businesses evolve and adapt to

proven new technologies. This not only helps businesses fully utilize their IT investment but also

helps them become leader in the very competitive market.

From medium businesses to large enterprises the storage need is almost doubled every year if

not increased by more. Therefore, businesses have big decisions to make when investing in

their SAN environment. This is certainly not to emphasize investing only in storage that may be

required in three years time. So, the question is: what should businesses' do? This is a big

question for every business these days, and EMC has been very successful over the decade to

provide the best answer with many proven solutions. One of those solutions is to be able to

migrate storage from legacy storage arrays onto new arrays without the hassle of losing data or

extensive downtime to the production environment.

SAN Copy is one of the many solutions that EMC has put forward for SAN migration. SAN

Copy is not a new product, having been in the market for many years. Therefore it is a proven

product for high-speed data mobility, migration, and protection between EMC CLARiiON

networked storage and other storage systems that are qualified by EMC. These systems include

EMC CLARiiON, EMC Symmetrix, IBM, HDS, and Sun storage arrays.

This Knowledge Sharing article focuses on the process and procedure involved in the SAN

Copy migration between two CLARiiON arrays. This is based on the process I followed that led

to a successful SAN Copy migration of multiple hosts from a CLARiiON array CX500 to CX4-

480.

The following step-by-step processes are discussed in this article.

1. Introduction

2. Basic Requirements

3. Zoning Requirements

4. Allocate destination Logical Unit Number (LUN)

5. Create SAN Copy Connection

6. Create SAN Copy Sessions

7. Host Preparation

8. Starting SAN Copy Sessions


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9. Monitoring SAN Copy Sessions

10. Completing the SAN Copy Session

11. Troubleshooting

12. Reference

13. Appendix

Introduction

SAN Copy copies data directly from a source LUN to a destination LUN without using host

resources. It copies data at block-level rather than file-level mechanism used by other third

party data migration tools. SAN Copy allows full or incremental copy of data from the source

LUN to destination. As the name implies, an incremental copy copies only the data that is

changed since the last copy session while full copy copies all data from source to the

destination LUN. Incremental SAN Copy has a few more requirements than Full which are

discussed later in this article. Also this article focuses on the detailed steps required for

successful SAN Copy data migration.

Basic Requirements

The following basic requirements must be met for a successful SAN Copy data migration.

a. All CLARiiON storage systems must be running Access Logix software.

b. One of the CLARiiON storage systems participating in the copy session must be a SAN

Copy storage system, meaning that the storage system must have a SAN Copy licenseinstalled.

c. Source and destination arrays must be correctly zoned. (e.g. MirrorView port must not

be used for SAN Copy if that CLARiiON system is using that feature) Zoning

requirements are discussed next.

d. Stop all I/O to the source and destination LUN before starting the copy session.

Along with the requirements above, the following must be met for Incremental SAN

Copy:

e. Source LUN must reside on SAN Copy storage system.

f. The source LUN cannot be a Snap View snapshot.

g. Reserve LUN pool must be configured and have at least one LUN for each source LUN

that will participate on the SAN Copy session.


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Zoning Requirements

SAN Copy can be performed within a CLARiiON storage system; in this case no new zoning

is required. However, if the SAN Copy is being performed with remote storage systems, new

zones need to be created. Basically, two different zones need to be added.

Host to New Storage Array

SAN Copy Zones between two Storage systems

For illustration purposes, SAN Copy zones with remote CX series CLARiiON system arediscussed below.

In the diagram above, the following zones are configured.

a. Source SPA1 zoned to Destination SPA1

b. Source SPA1 zoned to Destination SPB1

c. Source SPB1 zoned to Destination SPA1

d. Source SPB1 zoned to Destination SPB1

As seen, there are redundant connection paths from the source storage system (SAN Copy

storage system) to the destination storage system ensuring that each SP from a SAN Copy

storage system has access to each SP on a destination storage system.

EMC recommends configuring single initiator zoning so that there is no zoning conflict

between zone members. Also, avoid using the MirrorView port (highest port on the array usually port 3) for SAN Copy as MirrorView and SAN Copy cannot share the same port.

However, port 3 can be used if there is no MirrorView configured on the array.

Single initiator zoning means that you should only put one initiator in one zoneset and create

multiple zonesets for each initiator.


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Allocate Destination LUN

Destination LUN refers to the LUN where the data will be migrated. There is no restriction on

the size of destination LUN as long as it is bigger than the source LUN and is within the

supported range of the arrays that are participating on the SAN Copy session. However, the

recommendation is to use exact size LUN. This will be helpful if you need to restore from the

destination LUN back to the source should things go wrong.

Another tip when creating LUN is to base on the User Block size rather than User

Capacityor Raw Capacity.

On the LUN properties window, refer to the Capacity section to find the User Blocks of the

particular LUN. Refer to the image below.


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Create SAN Copy Sessions

Create Sessions on the array where the SAN Copy is enabled (Licensed).

You can create SAN Copy sessions in different ways. Simply, expand the storage system

and right click on SAN Copy Sessions. The wizard will display and take you through the

few steps that are required. Click Next.

On the Select Session Type window, select Full or Incremental and click Next. Here, we

only discuss Full SAN Copy session.

For incremental session, you must have SAN Copy license installed on the source array.

Here you will need to select the source LUN. If your source and destination storage systems

are on the same domain, you can select your source storage system from the Storage

Source drop down list. Otherwise, click on the Enter WWN button at the bottom left.


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Once you enter the LUNs WWN, click OK. Then click Next.

A new windowSelect Storage Destinations for Storage Sourceswill be displayed.

Here your selected LUN will be displayed.

Right click on the LUN and click on Select Destination Storage.

Find the LUN you created earlier and move across by clicking the Right arrow.

Then, click OK. Also make sure the Verify Connections check box is ticked so that the

communication between source and destination LUNs will be verified once you complete

this step. This will enable you to immediately troubleshoot any connectivity issues.

If the connection is successful, a message will display All the logical units are accessible.

Click OK.

The Session Names window will be displayed. You can select the default session name

and edit the name (if you are creating many sessions, its ideal to input appropriate names).

The throttle value of 6 is configured by default but can be changed later if you wish to do so.


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Changing throttle value to high may impact the resource allocated to other processes by the

array, as the array will dedicate more resources to complete the session.

Click Next. The SAN Copy Session Summary window will be displayed. Read the

information there carefully and verify that all information is correct.

Click Finish.

A Success message will be displayed. If you get a failure message, please troubleshoot

accordingly.

To view your sessions, expand the storage array, expand SAN Copy Sessions, expand

SPA Sessions or SPB Sessions and then expand the appropriate session types ; in this

instance, Full Sessions. Full SAN Copy Sessions created under this SP will be displayed

and marked as Not Started; 0%.

As mentioned earlier if you have both source and destination arrays on the same domain,

you can simply choose the LUN from the list rather than entering the WWNs. Simply select

the source/destination array from the drop down list and a list of LUNs will be displayed.

Host Preparation

a. Even though the risk of data corruption is none or nominal, it is recommended to take a

full backup of the LUNs participating on the migration before starting the SAN Copy

sessions.

b. Quiesce all writes to the source LUN.

c. Run the following commands respectively to ensure the server buffers are flushed and

drives are taken offline.

admhost lun_flusho source-drive letter or destination-drive letter

admhost lun_deactivateo source-drive letter or destination-drive letter


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d. Verify if the host requires OS patches, PowerPath upgrade HBA, firmware/driver upgrade,

and so on. If need be, upgrade these components prior to commencing the migration.

Note: If you do not have admhost utility installed in your environment, you can gracefully

shut down the application and then the servers so the OS will flush the remaining I/O to the

disk. In Full SAN Copy sessions, host and application should remain shut until the SAN

Copy is completed while on Incremental sessions, you can resume the host and application

activities once they are marked for SAN Copy session. You can also pause and resume

SAN Copy sessions anytime.

Start the SAN Copy Sessions

Starting SAN Copy Sessions is an easy task as we already prepared the sessions.

However, it is very important that a few things are checked before starting the session.

a. For Full SAN Copy Session, make sure host I/O is flushed using admhost utility as

explained earlier and there is no I/O on the source LUN.

b. Right click the sessions to verify the correct source and destination LUNs, Session

Throttle value, and SP Owner of Session. It is recommended that you not run the SAN

Copy session if you have very high workload on the arrays. However, If you need to run

the session, set the throttle value to low so migration doesnt impact the other production

activities.

Throttle Value: Throttle value controls the speed of data transfer between source and the

destination array. You can set the values between 1 and 10; 10 being the highest value.Throttle value can be changed while SAN Copy is in progress. Default value is 6.

c. Start the SAN Copy sessions.

Expand the storage system, then expand SAN Copy Sessions.

Expand the session type on the SP where you have created your session.

Session name will be displayed. If you havent chosen a name, a session default name

will be displayed (as below).

To start the SAN Copy session, simply right click the Session Name and then click Start.


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Monitoring the SAN Copy Session

You can monitor the progress of each SAN Copy session by simply browsing to the location

display on the screenshot above (Storage system > SAN Copy Sessions > Full Sessions).

You can also pause or stop the sessions as well as increase the throttle value of the

sessions. Default throttle value is six, with one being the lowest and 10 the highest.

Consider other array activities while increasing throttle value. Also monitor the SP statistics

to make sure the SP is not overloaded (Right click on SPA or SPB >properties > Statistics).

Completing the SAN Copy Session

Once the SAN Copy session is completed, perform the following steps to mount new LUNs

to the hosts.

e. Activate Zones

i. ADDHost to NEW storage systemii. RemoveHost from OLD storage system

f. Remove host from the storage group of Source storage system . Before removing

the host from the storage group, write down the Host LUN ID (HLU) numbers for

each LUN. These will need to match when the LUNs are added from the new storage

system after the migration.


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To check the HLUs, go to the particular storage group > Right Click > Properties.

Click on the Storage tab. Here you will find LUN Name, LUN ID, and Host LUN ID

(HLU). See below for reference.

g. Register host to the new storage system

h. Create storage group for the host (if you havent already done so ). You can also

create storage group and add LUNs to the storage group prior to starting the SAN

Copy sessions.

i. Add LUNs to the Storage group When you add LUNs, check the HLU numbers

recorded on step b above. Assign LUNs in order and make sure corresponding

LUNs (Source and Destination) have the same HLUs.

Please note that once the LUNs are added to the storage group, you cannot change

the Host LUN ID without removing it from the storage group. If you add a LUN with


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an incorrect HLU, remove the LUN from the storage group and add it again with the

correct HLU.

j. Add hosts to the Storage group.

k. Run admhost lun_activate source/destination-drive letter to remount the LUN.

l. Host should now see LUNs from the new storage system. Once the LUNs are visible

and accessible, start the applications.

m. Migration completed.

Note: If you have the latest Navisphere Host Agent installed on the host, it will

automatically register itself to the new CLARiiON array, providing the zones are

already enabled. Right click on the array and click connectivity status to verify

whether the host is registered. If it is, then simply add to the storage group to access

the LUNs. If admhost utility wasnt being used and host and application were down

during the migration process, bring the host online only after it is added to the

storage group and appropriate LUNs are assigned to that storage group. This will

avoid any host panic and further reboot to detect the new LUNs.


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Terminology

SAN Storage Area Network

LUN Logical Unit Number

HLU Host LUN ID

Access Logix

Feature of CLARiiON Flare software that controls LUN

access

SP Service Processor

admhost

An executable utility that can be run interactively via

script

Zone

Communication path between the source and

destination

Zoneset Group of initiator and target in a zone

Snapshot Point in time view of a source LUN

Reserved LUN

Pool

Collection of LUNs used to support the pointer-based

design of SnapView

Source LUN The LUN containing production data

Initiator Source of communication (e.g. HBAs)

Target Communication Target (e.g. FA , SPs)

References

n. CLARiiON HELP file

o. EMC White Paper: EMC CLARiiON SnapView Snapshots and snap sessions

knowledge book.

p. EMC White Paper: EMC CLARiiON SAN Copy

Appendix

A. Incremental SAN Copy session

Incremental SAN Copy feature is used more for data mobility than data migration.

However, it is still widely used for migration purposes as well. This feature becomes

handy when there is a large amount of data to be migrated and a customer cannot

afford extended downtime. Incremental session can be started and left running or

even paused while production work can continue from the source LUN. SAN Copy


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session then only copies the data that has changed since the last update. It utilizes

reserved LUN pool to handle this situation.

B. Configuring Reserve LUN pool for Incremental SAN Copy session

a. Create number of LUNs as per your requirements.

Note: General guideline of reserved LUN size is about 10-20% of source LUN

but this may vary due to other variables in your environment. The following

considerations can also be used as a guideline.

i. Rate of change of source LUN data

ii. Expected concurrent session count

iii. Expected duration of incremental SAN Copy session

iv. Expected snapshot write rate

b. In the Enterprise Storage dialogue box, click the Storage tab.

c. Double click the icon for the storage system you want to configure as the

reserve LUN pool.

d. Right-click the Reserved LUN Pool icon, and then click Configure.

e. In Available LUNs, select the LUNs that you created earlier and add to the

reserve LUN pool.

(Note: Thin LUNs cannot be added to the reserved LUN pool)

C. High level steps for Windows Cluster Migration

a. Stop all applications that use CLARiiON storage. Write down previous startup

settings and change application startup settings to manual.

b. From cluster administrator, take all virtual servers and cluster resources

offline based on dependencies.

c. Disable cluster services on passive node and set startup type to disable.

Once this is confirmed on passive node, repeat the same processes on active

node.

d. Un-zone servers from existing CLARiiON.e. Clean up PowerPath dead paths to existing CLARiiON LUNs.

f. Create Full SAN Copy session sessions between each source and target

LUNs.

g. Start the SAN Copy sessions.


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h. Increase the SAN Copy throttles value if necessary; default is 6 and

maximum is 10.

i. While data is being copied, update the Navisphere host agent on the host (if

needed).

j. Create zoning between the servers and new CLARiiON.

k. Ensure hosts are registered and logged in to the new array.

l. Wait until the SAN Copy sessions are completed for all LUNs.

m. Add the last Active Node and all the required LUNs to Storage group on the

new CLARiiON.

n. Perform a rescan in Disk Manager to discover LUNs from new array. Do not

proceed until all required LUNs are visible.

o. On the last active node, start the cluster service from the service console. Set

the service startup type back to Automatic.

p. On the last active node, launch cluster administrator and log in to the local

host. Start the cluster groups and ensure all the resources in the group are

started. Do not proceed until this is the case.

q. Start virtual servers and other cluster resources based on dependencies.

Ensure all the cluster resources are able to start on Active node.

r. Add the passive node to the storage group. This storage group should

already have the active node and all the required disks.s. Perform a rescan in Disk Manager to discover LUNs from the new array. Disk

may appear as unavailable because they are managed by active node.

t. On the last passive node, start the cluster service from the service console.

Set the service startup type back to automatic.

u. On Active node, refresh cluster administrator to discover the passive node.

v. Perform failover testing. Ensure cluster resources can be failed over and

failed back to and from passive node. First attempt of cluster failover after the

data migration may take longer. Do not restart or reboot machine while the

failover process is occurring.

w. Once the cluster failover is tested successfully, perform testing on

applications running on the cluster.

x. Remove SAN Copy sessions once application testing and data verification

are successful.


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y. SAN Copy data migration completes.

D. HBA Driver upgrade Windows 2003

Before proceeding to the steps below, download the required drivers for the HBAs.

Check EMC Powerlink for compatibility matrix.

a. Start the Device Manager:

I. Click Start and then click Run.

II. In Open, type devmgmt.msc, then press ENTER.

b. Use the scroll bar to scroll down the list of hardware types, and then double-

click SCSI and RAID controllers.

c. Double-click QLogic Fibre Channel HBA from the devices list.

d. Select the Driver tab, then click Update Driver to start the Hardware Update

Wizard.

e. Select "Install from a list or specific location (Advanced)" and click Next.

f. Select "Don't search I will choose the driver to install" and click Next.

g. Click Have Disk and navigate to the folder containing the extracted driver.

h. When the Hardware Update Wizard/Select a Device Driver dialog box opens,

click Next.

i. Click Finish on the Hardware Update Wizard/Completing the Hardware

Update Wizard.

j. Reboot the server.

EMC believes the information in this publication is accurate as of its publication date. The

information is subject to change without notice.

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2011ks pahari-san copy data migration a complete experience

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