This article indicates the main feature of EMC Federated Live Migration (FLM) and provides some FLM examples of SymCli commands.

Data migration has been a big challenge to storage administrator. With the increasing of the complexity of IT environment, the storage administrators have to be very careful when plan the migration process. To achieve non-destructive migration is also a difficult task.

Federated Live Migration ties together the array-based migration of the data, provided by EMC Open Replicator for Symmetrix, with the host-level application redirection, provided by multi-pathing software, such as EMC PowerPath, Veritas DMP or host –side MPIO software. It does this by using a set of coordinated commands through EMC’s SymCli to initiate the migration session and coordinate the host application redirection from one central point, making the migration truly non-disruptive. Additionally, Federated Live Migration supports a number of pre-qualified stacks of arrays, and host operating systems that help eliminate time-consuming remediation processes. Federated Live Migration is flexible. It’s capable of supporting combinations of migrating thick-to-thick, thick-to-thin, and thin-to-thin, as well as consolidating multiple systems to one Symmetrix.

Federated Live Migration has several features and benefits. It provides non-disruptive data migration from Symmetrix DMX to VMAX, or VMAX to VMAX. A planned outage must be taken at a convenient time for restoration of native identities. It leverages intelligence of storage array and host multi-pathing, and supports thick to thin migrations with Zero Space Reclaim. It also manages both array and host redirection with EMC’s SymCli command set.

The most common use cases for Federated Live Migration are one-way data migrations in support of data center consolidations and technology refreshes.

Some customers work to keep all the data for a given application in the same array, in which case, the growth of data in one array may need some applications to be moved to other storage. This is another example of where FLM would be useful.

Following illustrations indicate the FLM Migration flow and the steps required to migrate an application environment from an old DMX to a new VMAX platform. Each illustration is numbered.

• The first illustration shows an application host running production on a DMX array.
• The second image illustrates a zone that was created between the VMAX front-end port and the DMX front-end port (FAs).
• Illustration number three shows that a zone has been created between the HBA of the application host and the front-end port of the VMAX array.

• Step four shows the new device has been created on the VMAX. It’s mapped to the front-end port, however, it’s not yet masked to the HBA. Between step four and five, a FLM session has been created, resulting in the new VMAX device being set to host as passive.
• In step five, the VMAX devices are masked to the application host.

Upon activating the FLM session, the new VMAX device is set to host as active. The DMX device is set to host as passive. An Open Replicator Hot Pull session with Donor Update has been started on the VMAX. At this time, host I/O starts flowing to the VMAX device (shown in step six). New writes to the VMAX device will also be written to the DMX device because Donor Update is in use.

Once the migration completes, the FLM session reaches a copied state. Until the session is terminated, the old DMX devices continue to be updated. At this time, the session can be terminated.

The old DMX device can now be removed from the application host. The masking and zoning relationships with the application host can also be removed. The DMX can now be physically removed from the SAN.

Following is the FLM SymCli example:

1.To create a command file which includes ORS Pull Session’s source and target devices:

## FLM PAIR FILE

##

## COLUMN1: FLM Target [ VMAX - 5875 ]

## COLUMN2: FLM Source [ DMX - 5671 ]

symdev=000194900275:0328 symdev=000187490076:0720

symdev=000194900275:0329 symdev=000187490076:075F

symdev=000194900275:032A symdev=000187490076:07B6

symdev=000194900275:032B symdev=000187490076:07E9

2.Use symrcopy create –pull –migrate command to create a NoCopy FLM session:

symrcopy -f win_flm create -pull -migrate -host_type windows -mp_type ppath_45

3.Use symrcopy query command to valid FLM pairs is in the Migration Session with Created State.

symrcopy -f win_flm query

Device File Name : win_flm

       Control Device                  Remote Device      Flags      Status Done

---------------------------- --------------------------- ------- -------------- ----

Protected

SID:symdev Tracks    Identification           RI CDSHUTZ  CTL <=> REM    (%)

------------------ --------- ------------------------ -- ------- -------------- ----

000194900275:0328 60000 000187490076:0720        SD ...XXM. Created         N/A

4. Create device mapping and masking on VMAX array:

symaccess –sid 275 create view -name win_flm_mv -sg win_flm_sg -pg win_flm_pg  -ig win_flm_ig

symaccess -sid 275 show view win_flm_mv

5. Verify devices are show up from host side:

powermt display dev=all

Pseudo name=harddisk14

Symmetrix ID=000187490076

Logical device ID=0720

state=alive; policy=SymmOpt; priority=0; queued-IOs=0

==============================================================================

---------------- Host ---------------   - Stor - -- I/O Path -  -- Stats ---

### HW Path                 I/O Paths    Interf. Mode    State  Q-IOs Errors

==============================================================================

   5 port5\path0\tgt10\lun6    c5t10d6   FA 14cA active  alive      0 0

   5 port5\path0\tgt11\lun6    c5t11d6   FA 14cB active  alive      0 0

   5 port5\path0\tgt4\lun1     c5t4d1    FA 7eC   active  dead 0      1

   5 port5\path0\tgt6\lun1     c5t6d1    FA 8eC   active  dead 0      1

6. Activate FLM session

symrcopy -f win_flm activate -migrate

7. Confirm the data is being copied:

symrcopy -f win_flm query

Device File Name : win_flm

       Control Device                  Remote Device      Flags Status    Done

---------------------------- --------------------------- ------- -------------- ----

Protected

SID:symdev Tracks    Identification           RI CDSHUTZ  CTL <=> REM    (%)

------------------ --------- ------------------------ -- ------- -------------- ----

000194900275:0328 45580 000187490076:0720        SD X..XXM. CopyInProg       24

000194900275:0329 45399 000187490076:075F        SD X..XXM. CopyInProg       24

000194900275:032A 45411 000187490076:07B6        SD X..XXM. CopyInProg       24

000194900275:032B 550 000187490076:07E9        SD X..XXM. CopyInProg       96

Total ---------

  Track(s)            136940

  MB(s)               8558.8

8. Confirm the application is switched over from DMX to VMAX:

powermt display dev=all

Pseudo name=harddisk14

Symmetrix ID=000187490076

Logical device ID=0720

state=alive; policy=SymmOpt; priority=0; queued-IOs=0

==============================================================================

---------------- Host ---------------   - Stor - -- I/O Path -  -- Stats ---

### HW Path                 I/O Paths    Interf. Mode    State  Q-IOs Errors

==============================================================================

   5 port5\path0\tgt10\lun6    c5t10d6   FA 14cA active  dead       0 1

   5 port5\path0\tgt11\lun6    c5t11d6   FA 14cB active  dead       0 1

   5 port5\path0\tgt4\lun1     c5t4d1    FA 7eC   active  alive 0      1

   5 port5\path0\tgt6\lun1     c5t6d1    FA 8eC   active  alive 0      1

9. Confirm the copy session is completed after a while:

symrcopy -f win_flm query

Device File Name      : win_flm

Control Device Remote Device      Flags      Status Done

---------------------------- --------------------------- ------- -------------- ----

                   Protected

SID:symdev         Tracks    Identification           RI CDSHUTZ  CTL <=> REM    (%)

------------------ --------- ------------------------ -- ------- -------------- ----

000194900275:0328          0 000187490076:0720        SD X..XXM. Copied          100

000194900275:0329          0 000187490076:075F        SD X..XXM. Copied          100

000194900275:032A          0 000187490076:07B6        SD X..XXM. Copied          100

000194900275:032B          0 000187490076:07E9        SD X..XXM. Copied          100

Total              ---------

Track(s)                 0

MB(s)                  0.0

...

C:\> symrcopy -f win_flm verify

All device(s) in the list are in 'Copied' state.

10. Terminate the FLM session:

symrcopy -f win_flm terminate -migrate

Author: Fenglin Li

          

iEMC APJ

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