Dell POWERVAULT MD3620I - Manual (Page 119)

Configuration: Disk Groups and Virtual Disks 119
Changing the Segment Size of a Virtual Disk
You can change the segment size on a selected virtual disk. During this
operation, I/O performance is affected, but your data remains available.
Guidelines to proceed with changing the segment size:
• You cannot cancel this operation after it starts.
• Do not start this operation unless the disk group is in Optimal status.
• MDSM determines the segment size transitions that are allowed. Segment
sizes that are inappropriate transitions from the current segment size are
unavailable on the menu. Allowed transitions usually are double or half of
current segment size. For example, if the current virtual disk segment size
is 32 KB, a new virtual disk segment size of either 16 KB or 64 KB is
allowed.
NOTE: The operation to change the segment size is slower than other modification
operations (for example, changing RAID levels or adding free capacity to a disk
group). This slowness is the result of how the data is reorganized and the temporary
internal backup procedures that occur during the operation.
The amount of time that a change segment size operation takes depends on:
• The I/O load from the host
• The modification priority of the virtual disk
• The number of physical disks in the disk group
• The number of physical disk ports
• The processing power of the storage array RAID controller modules
If you want this operation to complete faster, you can change the
modification priority, although this may decrease system I/O performance.
To change the segment size of a virtual disk:
1 In the AMW, select the Logical tab and select a virtual disk.
2 Select Virtual Disk Change Segment Size.
3 Select the required segment size.
A message prompts you to confirm the selected segment size.
4 Click Yes.
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