Migration process management

You can initiate volume migrations and pause, resume, or cancel a migration process that is in progress.

Volumes that are eligible for migration are dependent on the state and access of the volumes. Table 1 shows the states that are required to allow migration with Easy Tier®.
Table 1. Volume states required for migration with Easy Tier
  Volume state Is migration allowed with Easy Tier?
Access state Online Yes
Fenced No
Data state Normal Yes
Pinned No
Read only Yes
Inaccessible No
Indeterminate data loss No
Extent fault No

Initiating volume migration

With Easy Tier, you can migrate volumes from one extent pool to another. The time to complete the migration process might vary, depending on what I/O operations are occurring on your storage unit.

If an error is detected during the migration process, the storage facility image (SFI) attempts the extent migration again after a short time. If an extent cannot be successfully migrated, the migration is stopped, and the configuration state of the logical volume is set to migration error.

Pausing and resuming migration

You can pause volumes that are being migrated. You can also resume the migration process on the volumes that were paused.

Canceling migration

You can cancel the migration of logical volumes that are being migrated. The volume migration process pre-allocates all extents for the logical volume when you initiate a volume migration. All pre-allocated extents on the logical volume that are not migrated are released when you cancel a volume migration. The state of the logical volumes changes to migration-canceled and the target extent pool that you specify on a subsequent volume migration is limited to either the source extent pool or target extent pool of the original volume migration.

Note: If you initiate a volume migration but the migration was queued and not in progress, then the cancel process returns the volume to normal state and not migration-canceled.