Administrator Guide
Table Of Contents
- Dell EMC Storage Systems Administrator Guide for PowerStore and Unity XT metro node feature
- CLI Workspace and User Accounts
- Meta Volumes
- System Management
- Thin support in metro node
- Provisioning Storage
- Volume expansion
- Data migration
- About data migrations
- Migrating thin-capable storage
- About rebuilds
- One-time data migrations
- Batch migrations
- Prerequisites
- Creating a batch migration plan
- Checking a batch migration plan
- Modifying a batch migration file
- Starting a batch migration
- Pausing/resuming a batch migration (optional)
- Canceling a batch migration (optional)
- Monitoring a batch migration’s progress
- Viewing a batch migration’s status
- Committing a batch migration
- Cleaning a batch migration
- Removing batch migration records
- Configure the WAN Network
- Consistency Groups
- Performance and Monitoring
- Metro node with active-passive storage arrays
- Index
Table 5. Migration scenarios (continued)
Migration Virtual volume state before
migration
Virtual volume state during
migration
Virtual volume state after
migration
NOTE: In this case,
UNMAP is intentionally
disabled.
Thin to thick (Thin-enabled
virtual volume)
Thin-capable = true Thin-capable = false Thin-capable = false
Thin-enabled = enabled Thin-enabled = enabled Thin-enabled = unavailable
UNMAP processed UNMAP rejected UNMAP rejected
Thin to thick (Non thin-
enabled virtual volume)
Thin-capable = true Thin-capable = false Thin-capable = false
Thin-enabled = disabled Thin-enabled = unavailable Thin-enabled = unavailable
UNMAP rejected UNMAP rejected UNMAP rejected
NOTE:
● During migration, a temporary mirror is created to move data from the migration source to the target. Metro node
processes UNMAP commands only when both the thin-capable and the thin-enabled attributes are set to
true on the virtual volume.
● If the target of migration is a thin-capable device of larger capacity than the source device, then metro node virtual
volumes continue to be thin-capable and preserves the earlier provisioned thin-enabled property after the migration
completes. To leverage unused capacity, use the virtual-volume expand command.
When migrating from a thin-enabled device to a non-thin device (such as thick device), the volume's thin-enabled attribute
stays as enabled although UNMAP is rejected during the migration. After the migration completes successfully, the
thin-enabled attribute becomes unavailable because the target device is thick. This behavior is intended because the
volume reverts to a thin volume when migration is aborted or failed."
Consider the following when running one time migrations:
● In a thin to thick extent or device migration (with supported virtual volume), if the source is thin-capable and the target is
not thin-capable, the supported virtual volumes are not thin-enabled or thin-capable after migration.
VPlexcli:/clusters/cluster-1/devices> dm migration start --paused --name my_migration
--from thin_source
--to device_thick_1
The source 'thin_source' is thin-capable but the target 'device_thick_1' is not thin-
capable. The
virtual-volume 'thin_source_vol' will not be thin-enabled or thin-capable after
migration.
Do you wish to proceed? (Yes/No) no
dm migration start: Evaluation of <<dm migration start --paused --name my_migration
--from thin_source/
--to device_thick_1_c1/>> failed.
cause: Failed to create a new data-migration.
cause: Operation was halted by the user
VPlexcli:/clusters/cluster-1/devices>
VPlexcli:/clusters/cluster-1/storage-elements/extents> dm migration start --paused --
name my_migration
--from thin_extent_1 --to thick_extent_1
The source 'thin_extent_1' is thin-capable but the target 'thick_extent_1' is not
thin-capable.
The virtual-volume 'thin_source_vol' will not be thin-enabled or thin-capable after
migration.
Do you wish to proceed? (Yes/No) no
dm migration start: Evaluation of <<dm migration start --paused --name my_migration
--from extent_20
--to extent_31>> failed.
cause: Failed to create a new data-migration.
Data migration
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