Configuration: Disk Groups and Virtual Disks 111Changing the Segment Size of a Virtual DiskYou can change the segment size on a selected virtual disk. During thisoperation, 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. Segmentsizes that are inappropriate transitions from the current segment size areunavailable on the menu. Allowed transitions usually are double or half ofcurrent segment size. For example, if the current virtual disk segment sizeis 32 KB, a new virtual disk segment size of either 16 KB or 64 KB isallowed.NOTE: The operation to change the segment size is slower than other modificationoperations (for example, changing RAID levels or adding free capacity to a diskgroup). This slowness is the result of how the data is reorganized and the temporaryinternal 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 modulesIf you want this operation to complete faster, you can change themodification priority, although this might 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.
