Dell POWERVAULT MD3620I - Manual (Page 48)

48 Planning: MD3600i Series Storage Array Terms and Concepts
• 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 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
before your perform 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 MD3600i Series
storage array to another, the MD3600i storage array you migrate to, recognizes
any data structures and/or metadata you had in place on the migrating
MD3600i storage array. However, if you are migrating from any device other
than a MD3600i Series storage array, the MD3600i storage array does not
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