Virtual Disk Migration And Disk Roaming; Disk Migration - Dell PowerVault MD3260i Administrator's Manual

• Rebuild
• Copy back
• Virtual disk capacity expansion
• Raid level migration
• Segment size migration
• Disk group expansion
• Disk group defragmentation
The priority of each of these operations can be changed to address performance requirements of the environment in
which the operations are to be executed.
NOTE: Setting a high priority level impacts storage array performance. It is not advisable to set priority levels at the
maximum level. Priority must also be assessed in terms of impact to host server access and time to complete an
operation. For example, the longer a rebuild of a degraded virtual disk takes, the greater the risk for potential
secondary disk failure.

Virtual Disk Migration And Disk Roaming

Virtual disk migration is moving a virtual disk or a hot spare from one array to another by detaching the physical disks
and re-attaching them to the new array. Disk roaming is moving a physical disk from one slot to another on the same
array.

Disk Migration

You can move virtual disks from one array to another without taking the target array offline. However, the disk group
being migrated must be offline prior to performing the disk migration. If the disk group is not offline prior to migration, the
source array holding the physical and virtual disks within the disk group marks them as missing. However, the disk
groups themselves migrate to the target array.
An array can import a virtual disk only if it is in an optimal state. You can move virtual disks that are part of a disk group
only if all members of the disk group are being migrated. The virtual disks automatically become available after the
target array has finished importing all the disks in the disk group.
When you migrate a physical disk or a disk group from:
• One MD storage array to another MD storage array of the same type (for example, from an MD3260 storage
array to another MD3260 storage array), the MD storage array you migrate to, recognizes any data structures
and/or metadata you had in place on the migrating MD storage array.
• Any storage array different from the MD storage array you migrate to (for example, from an MD3260 storage
array to an MD3260i storage array), the receiving storage array (MD3260i storage array in the example) does not
recognize the migrating metadata and that data is lost. In this case, the receiving storage array initializes the
physical disks and marks them as unconfigured capacity.
NOTE: Only disk groups and associated virtual disks with all member physical disks present can be migrated from
one storage array to another. It is recommended that you only migrate disk groups that have all their associated
member virtual disks in an optimal state.
NOTE: The number of physical disks and virtual disks that a storage array supports limits the scope of the
migration.
Use either of the following methods to move disk groups and virtual disks:
• Hot virtual disk migration — Disk migration with the destination storage array power turned on.
• Cold virtual disk migration — Disk migration with the destination storage array power turned off.
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