Dell PowerFlex Manager 4.6.x CLI Reference Guide

During V-Tree migration, you can run other tasks such as creating snapshots, deleting snapshots, and entering maintenance mode.

When a V-Tree migration is requested, the MDM first estimates whether the destination storage pool has enough capacity for the migration to complete successfully. The MDM bases the estimation on its information of the current capacity of the V-Tree. If there is insufficient capacity at the destination based on that estimate, migration does not start. (You can use the --ignore_destination_capacity option to force the migration even if there is insufficient capacity at the destination, with the intention to increase the capacity as required during the migration.) The MDM does not reserve the estimated capacity at the destination (since the capacity of the source volume can grow during migration and the reserved capacity does not guarantee success). The MDM does not hold onto source capacity once it has been migrated, but releases it immediately.

V-Tree migration can take a long time, depending on the size of the V-Tree and the system workload. During migration, the V-Tree is fully available for user I/O. V-Tree migration is done volume block by volume block. When a single block has completed its migration, the capacity of the block at the source becomes available, and it becomes active in the destination storage pool. During migration, the V-Tree has some of its blocks active in the source storage pool and the remaining blocks active in the destination storage pool.

When migrating from a medium granularity storage pool to a fine granularity storage pool, volumes must be zero padded.

Syntax

scli --migrate_vtree (--volume_id <ID> | --volume_name <NAME>) (((--destination_protection_domain_id <ID> | --destination_protection_domain_name <NAME>) --destination_storage_pool_name <NAME>) | --destination_storage_pool_id <ID>) 
  [--migration_queue_position {head_of_queue | tail_of_queue}] 
  [ --convert_to_thin_provisioned]
  [ --convert_to_thick_provisioned]
  [compression_method {none | normal}
  [--ignore_destination_capacity] 
  

Parameters

--volume_id <ID>

Volume ID of the V-Tree to be migrated

--volume_name <NAME>

Volume name of the V-Tree to be migrated

--destination_protection_domain_id <ID>

ID of the destination protection domain

--destination_protection_domain_name <NAME>

Name of the destination protection domain

--destination_storage_pool_name <NAME>

Name of the destination storage pool

--destination_storage_pool_id <ID>

ID of the destination storage pool

NOTE:The migrateVTree command is also used for rollback volume migration while using the destination_storage_pool_id.

--migration_queue_position {head_of_queue | tail_of_queue}

Define whether this migration should be placed at the head or the tail of the migration queue. By default, it is placed at the tail or it retains its position if the V-Tree is already in migration.

--convert_to_thin_provisioned

Convert a thick-provisioned V-Tree to be thin-provisioned.

NOTE: SDCs with a version earlier than v3.0 do not fully support converting a thick-provisioned V-Tree to a thin-provisioned V-Tree during migration; after migration, the V-Tree is thin-provisioned, but the SDC is unable to trim it. These volumes can be trimmed by unmapping and then remapping them, or by rebooting the SDC. The SDC version does not affect capacity allocation and a V-Tree converted from thick to thin provisioning is reduced in size accordingly in the system.

--convert_to_thick_provisioned

Convert a thin-provisioned V-Tree to be thick-provisioned.

compression_method {none | normal}

Indicate the compression method to be used, relevant only for fine granularity data layouts. By default, the compression is according to the settings of the destination storage pool.

--ignore_destination_capacity

Force migration, even if currently there is not enough capacity at the destination.