Dell PowerVault MD3260i CLI Guide - Page 83

Changing RAID Levels, Changing Segment Size, Defragmenting A Disk Group

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Changing RAID Levels When creating a disk group, define the RAID level for the virtual disks in that group. You can later change the RAID level to improve performance or provide more secure protection for your data. To change the RAID level, run the following command: set diskGroup [diskGroupNumber] raidLevel=(0|1|5|6) where, diskGroupNumber is the number of the disk group for which to change the RAID level. Changing Segment Size When creating a new virtual disk, define the segment size for that virtual disk. You can later change the segment size to optimize performance. In a multi-user database or file system storage environment, set your segment size to minimize the number of physical disks needed to satisfy an I/O request. Use larger values for the segment size. Using a single physical disk for a single request leaves other disks available to simultaneously service other requests. If the virtual disk is in a single-user large I/O environment, performance is maximized when a single I/O request is serviced with a single data stripe; use smaller values for the segment size. To change the segment size, run the following command: set virtualDisk ([virtualDiskName] | ) segmentSize=segmentSizeValue where, segmentSizeValue is the new segment size you want to set. Valid segment size values are 8, 16, 32, 64, 128, 256, and 512. You can identify the virtual disk by name or World Wide Identifier (WWID) (see Set Virtual Disk). Defragmenting A Disk Group When you defragment a disk group, you consolidate the free capacity in the disk group into one contiguous area. Defragmentation does not change the way in which the data is stored on the virtual disks. As an example, consider a disk group with five virtual disks. If you delete virtual disks 1 and 3, your disk group is configured in the following manner: space, virtual disk 2, space, virtual disk 4, virtual disk 5, original unused space When you defragment this group, the space (free capacity) is consolidated into one contiguous location after the virtual disks. After being defragmented, the disk group is: virtual disk 2, virtual disk 4, virtual disk 5, consolidated unused space To defragment a disk group, run the following command: start diskGroup [diskGroupNumber] defragment where, diskGroupNumber is the identifier for the disk group. NOTE: Defragmenting a disk group starts a long-running operation. Troubleshooting and Diagnostics If a storage array exhibits abnormal operation or failures, you can use the commands described in this section to determine the cause of the problems. 83

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Changing RAID Levels
When creating a disk group, define the RAID level for the virtual disks in that group. You can later change the RAID level
to improve performance or provide more secure protection for your data. To change the RAID level, run the following
command:
set diskGroup [diskGroupNumber] raidLevel=(0|1|5|6)
where,
diskGroupNumber
is the number of the disk group for which to change the RAID level.
Changing Segment Size
When creating a new virtual disk, define the segment size for that virtual disk. You can later change the segment size to
optimize performance. In a multi-user database or file system storage environment, set your segment size to minimize
the number of physical disks needed to satisfy an I/O request. Use larger values for the segment size. Using a single
physical disk for a single request leaves other disks available to simultaneously service other requests. If the virtual disk
is in a single-user large I/O environment, performance is maximized when a single I/O request is serviced with a single
data stripe; use smaller values for the segment size. To change the segment size, run the following command:
set virtualDisk ([virtualDiskName] | <
wwid
>)
segmentSize=
segmentSizeValue
where,
segmentSizeValue
is the new segment size you want to set. Valid segment size values are
8
,
16
,
32
,
64
,
128
,
256
, and
512
. You can identify the virtual disk by name or World Wide Identifier (WWID) (see Set Virtual Disk).
Defragmenting A Disk Group
When you defragment a disk group, you consolidate the free capacity in the disk group into one contiguous area.
Defragmentation does not change the way in which the data is stored on the virtual disks. As an example, consider a
disk group with five virtual disks. If you delete virtual disks 1 and 3, your disk group is configured in the following manner:
space, virtual disk 2, space, virtual disk 4, virtual disk 5, original unused space
When you defragment this group, the space (free capacity) is consolidated into one contiguous location after the virtual
disks. After being defragmented, the disk group is:
virtual disk 2, virtual disk 4, virtual disk 5, consolidated unused space
To defragment a disk group, run the following command:
start diskGroup [diskGroupNumber] defragment
where,
diskGroupNumber
is the identifier for the disk group.
NOTE:
Defragmenting a disk group starts a long-running operation.
Troubleshooting and Diagnostics
If a storage array exhibits abnormal operation or failures, you can use the commands described in this section to
determine the cause of the problems.
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