Changing The Pre-Read Consistency Check Setting Of An Overall Repository Virtual Disk - Dell EMC PowerVault MD Series Administrator's Manual

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 replicated physical disks. RAID Level 0 virtual
disks have no data consistency.
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
consistency 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 consistency 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.
Deleting Snapshot Virtual Disk or consistency group Snapshot Virtual Disk
Use the Delete Snapshot Virtual Disk option to delete a snapshot virtual disk or consistency group snapshot virtual disk that is no longer
needed for backup or software application testing purposes. You also can specify whether you want to delete the snapshot repository
virtual disk associated with a read-write snapshot virtual disk or a read-write consistency group snapshot virtual disk or retain the snapshot
repository virtual disk as an unmapped virtual disk.
When a snapshot virtual disk or consistency group snapshot virtual disk is deleted, the system performs the following actions:
• Deletes all member snapshot virtual disks—for a consistency group snapshot virtual disk.
• Removes all associated host mappings.
136 Premium feature—Snapshot Virtual Disk