Dell PowerVault MD3820f - Manual (Page 168)

5. Select either With consistency check or Without consistency check, and click OK.
A consistency check scans the blocks in a RAID Level 5 virtual disk, or a RAID Level 6 virtual disk and
checks the consistency information for each block. A consistency check compares data blocks on
RAID Level 1 mirrored physical disks. RAID Level 0 virtual disks have no data redundancy.
Changing The Pre-read Consistency Check Setting Of An Overall Repository
Virtual Disk
Use the Pre-Read Consistency Check option to define a storage array's capability to pre-read an overall
repository virtual disk consistency information and determine whether the data of that overall repository
virtual disk is consistent. An overall repository virtual disk that has this feature enabled returns read errors
if the data is determined to be inconsistent by the RAID controller module firmware. You can enable this
option for overall repository virtual disks that contain consistency information. RAID Level 1, RAID Level 5,
and RAID Level 6 maintain redundancy information.
You can enable this option for overall repository virtual disks that contain consistency information. RAID
Level 1, RAID Level 5, and RAID Level 6 maintain redundancy information.
You can change the Pre-Read Consistency Check for an overall repository for the following storage
objects:
• Snapshot group
• Snapshot virtual disk
• Consistency group member virtual disk
• Replicated Pair
The following guidelines apply:
• 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
ignores consistency pre-read. If the virtual disk is subsequently migrated back to a RAID level that
supports consistency, the option becomes available again.
To create a consistency group snapshot virtual disk:
1. From the AMW, select the Storage & Copy Services tab.
2. Select the storage object for which to change the pre-read consistency check settings.
3. Right click the select object and select Overall Repository → Change Pre-read Consistency Check.
4. Select Enable pre-read consistency check, and click OK.
NOTE: Enabling the option on overall repository virtual disks without consistency does not
affect the virtual disk. However, the attribute is retained for that overall repository virtual disk if it
is ever changed to one with consistency information.
5. Click Yes.
Increasing The Capacity Of An Overall Repository
An overall repository can contain multiple repository virtual disks. You can use the Increase Capacity
option to increase the storage capacity of an existing overall repository for the following storage objects:
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