Providing high availability with live migration in a Cluster Server environment

You can use Live Partition Mobility to perform a stateful migration of a logical partition (LPAR) in a Cluster Server (VCS) environment. VCS supports LPAR live migration in two ways:

VCS initiated LPAR migration

If VCS encounters an error while creating or deleting an LPAR configuration or VIOS mappings, then online or offline of LPAR resource stops immediately and does not recover from the intermediate state. Administrative intervention is required when an LPAR configuration or VIOS mappings creation or deletion fails.

Some limitations for LPM apply when VCS is configured to manage high availability of LPARs.

See Limitations and unsupported LPAR features.

For more information, refer to the Cluster Server Administrator's Guide.

LPAR migration outside of VCS control

To avoid false failovers for LPAR migration outside of VCS control

  1. Determine how long the migrating node is unresponsive in your environment.
  2. If that time is less than the default LLT peer inactive timeout of 16 seconds, VCS operates normally.

    If not, increase the peer inactive timeout to an appropriate value on all the nodes in the cluster before beginning the migration.

    For example, to set the LLT peerinact timeout to 90 seconds, use the following command:

    # lltconfig -T peerinact:9000

    The value of the peerinact command is in .01 seconds.

  3. Verify that peerinact has been set to 90 seconds:
    # lltconfig -T query
    Current LLT timer values (.01 sec units):
     heartbeat   = 50
     heartbeatlo = 100
     peertrouble = 200
     peerinact   = 9000
     oos         = 10
     retrans     = 10
     service     = 100
     arp         = 30000
     arpreq         = 3000
     Current LLT flow control values (in packets):
     lowwater  = 40
  4. Repeat steps 1 to 3 on other cluster nodes.
  5. Reset the value back to the default after the migration is complete.

To make LLT peerinact value persistent across reboots:

Some limitations for Live Partition Mobility (LPM) apply when VCS is configured to manage high availability of LPARs.

See Limitations and unsupported LPAR features.

For more information on VCS commands, see the Cluster Server Administrator's Guide.

For attributes related to migration, see the Cluster Server Bundled Agents Reference Guide.

To migrate the managed LPAR without ProfileFile support

  1. From the source managed system, back up the LPAR profile. After migration completes, the LPAR and its profiles are automatically deleted from the source.

    For VCS to manage the LPAR, the profile is required on the managed physical system of the management VCS that is part of the system list of the LPAR resource.

  2. On the destination system, rename the LPAR profile that was created during initial configuration of LPAR as a resource on all systems. LPM validation fails if it finds the profile with same LPAR name on the destination managed physical system
  3. Migrate the managed LPAR.
  4. Perform one of the following:
    • If migration succeeds, the profile on source is removed. Restore and rename the LPAR profile from the backup that was taken in step 1. Remove the renamed LPAR profile on the destination.

    • If migration fails, remove the backup profile on the source. On the destination, rename the renamed LPAR profile to original LPAR profile.