Dell PowerVault MD3260i - Manual (Page 108)

Consistency
mismatches
Consistency errors are found, and a media error is forced on the block stripe so that it
is found when the physical disk is scanned again. If consistency is repaired, this forced
media error is removed. The result of this action is that the first ten consistency
mismatches found on a virtual disk are reported to the MEL.
Unfixable error The data could not be read and consistency information could not be used to
regenerate it. For example, consistency information cannot be used to reconstruct
data on a degraded virtual disk. The result of this action is that the error is reported to
the MEL.
The script command set provides four commands to define media scan properties:
• set virtualDisks
• set storageArray
• set snapGroup
• set snapVirtualDisk
The set virtualDisk command enables a media scan for the virtual disk. The following syntax is the general form
of the command:
set (allVirtualDisks | virtualDisk
[virtualDiskName] | virtualDisks [virtualDiskName1
... virtualDiskNamen] | virtualDisk <wwid>
mediaScanEnabled=(TRUE | FALSE)
The set storageArray command defines how frequently a media scan is run on a storage array. The following
syntax is the general form of the command:
set storageArray mediaScanRate=(disabled | 1-30)
The set snapVirtualDisk and set snapGroup commands run media scans on physical disks that are
members of snapshots and snapshot groups. The following examples show command syntax:
set snapVirtualDisk ["snapvirtualDiskName"]
mediaScanEnabled=(TRUE | FALSE)
set snapGroup ["snapGroupName"]
mediaScanEnabled=(TRUE | FALSE)
Running A Consistency Check With A Media Scan
Consistency checks are performed when media scans are run, if consistency check is enabled on the virtual disk.
During a consistency check, all data blocks in a virtual disk are scanned, and deteriorated data is corrected. The method
of correction depends on the redundant array of independent disks (RAID) levels:
RAID 5 and RAID
6 virtual disks Consistency is checked and repaired.
RAID 1 virtual
disks The data is compared between the mirrored physical disks, and data inconsistencies are
repaired.
RAID 0 virtual
disks No redundancy exists.
NOTE: Do not run consistency checking commands on RAID 0 virtual disks.
Before attempting a consistency check, you must enable consistency checking using the set virtualDisk
command. Use the following command to set the consistencyCheckEnabled parameter to TRUE:
set (allVirtualDisks | virtualDisk
[virtualDiskName] | virtualDisks [virtualDiskName1
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