Dell PowerVault MD3420 - Manual (Page 66)

• Snapshot group
• Snapshot virtual disk
• Consistency group member virtual disk
• Replicated Pair
This command defines the properties for a virtual disk. You can use most parameters to define properties
for one or more virtual disks. You can also use some parameters to define properties for only one virtual
disk. The syntax definitions are separated to show which parameters apply to several virtual disks and
which apply to only one virtual disk.
NOTE: In configurations where disk groups consist of more than 32 virtual disks, the operation can
result in host I/O errors or internal RAID controller module reboots due to the expiration of the
timeout period before the operation completes. If you experience host I/O errors or internal RAID
controller module reboots, quiesce the host I/O and try the operation again.
Syntax Applicable To One Or More Virtual Disks
set (allVirtualDisks | virtualDisk ["virtualDiskName"] | virtualDisks
["virtualDiskName1" ... "virtualDiskNameN"] | virtualDisk <wwID>)
cacheFlushModifier=cacheFlushModifierValue cacheWithoutBatteryEnabled=(TRUE |
FALSE)
mediaScanEnabled=(TRUE | FALSE)
replicationCacheEnabled=(TRUE | FALSE)
modificationPriority=(highest | high | medium | low | lowest)
owner=(0 | 1)
preReadConsistencyCheck=(TRUE | FALSE)
readCacheEnabled=(TRUE | FALSE)
writeCacheEnabled=(TRUE | FALSE)
cacheReadPrefetch=(TRUE | FALSE)
Syntax Applicable To Only One Virtual Disk
set (virtualDisk ["virtualDiskName"] | virtualDisk <wwID>)
addCapacity=virtualDiskCapacity
[addPhysicalDisks=(enclosureID1,drawerID1,slotID1 ...
enclosureIDn,drawerIDn,slotIDn)]
consistencyCheckEnabled=(TRUE | FALSE) segmentSize=segmentSizeValue
userLabel=virtualDiskName
preReadConsistencyCheck=(TRUE | FALSE)
preReadConsistencyCheck
The setting to turn on or turn off preread consistency checking. Turning on preread consistency
checking verifies the consistency of RAID redundancy data for the stripes containing the read data.
Preread consistency checking is performed on read operations only. To turn on preread consistency
checking, set this parameter to TRUE. To turn off preread consistency checking, set this parameter to
FALSE.
NOTE: Do not use this parameter on non-redundant virtual disks, such as RAID 0 virtual disks.
Guidelines while using the Pre-Read Consistency Check option:
• Changing the Pre-Read Consistency Check setting modifies the setting only for the overall repository
that you selected.
• The Pre-Read Consistency Check setting is applied to all individual repository virtual disks contained
within the overall repository.
• If an overall repository virtual disk that is configured with pre-read is migrated to a RAID level that
does not maintain consistency information, the metadata of the overall repository virtual disk
continues to show that pre-read is enabled. However, reads to that overall repository virtual disk
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