HP P6000 Replication Solutions Manager User Guide (T3680-96089, October 2012)

• In basic asynchronous write mode, or synchronous write mode, its DR group log is logging
or merging. See Write mode and DR group log.
• In enhanced asynchronous write mode, its DR group log is logging, merging, or contains any
transactions to be merged.
Mirrorclone normalization
Mirrorclone normalization is a process that verifies that data is identical on a source virtual disk
and its synchronized mirrorclone. See Synchronized mirrorclones.
Some actions should not be performed during mirrorclone normalization. When creating jobs, use
wait commands to ensure that normalization is completed. See the
WaitStorageVolumeNormalization, WaitStorageVolumesNormalization, and
WaitVolumeGroupNormalization job commands.
Snapclone normalization (unsharing)
The snapclone normalization is a process which verifies that data is identical on a source virtual
disk and its snapclone, before the snapclone can become an independent disk (a point-in-time
copy). See Snapclones. Snapclone normalization is also called unsharing.
Some actions should not be performed during snapclone normalization. When creating jobs, use
wait commands to ensure that normalization is completed. See the
WaitStorageVolumeNormalization, WaitStorageVolumesNormalization, and
WaitVolumeGroupNormalization job commands.
Operational state - blocked
Blocked is an operational state of a DR group, or a virtual disk, that indicates if the array has
detected a potential replication issue and is preventing presentation of impacted source virtual
disks. See Presentation to hosts.
The presentation of virtual disks in a source DR group is blocked after power is cycled off and on
to both controllers in the source array and:
• The destination DR group was unavailable after power was cycled off and on in the source
array.
• Remote replication was not suspended after power was cycled off and on in the source array.
• The Destination mode was something other than Read Only after power was cycled off and
then on in the source array.
You can determine if disk presentation is blocked by checking the operational state of the DR group
or individual disk. See Viewing DR group properties and Viewing virtual disk properties.
Unblocking
The virtual disks in a source DR group are automatically unblocked when the destination DR group
becomes available again. You can manually unblock virtual disks by suspending the source DR
group in which they are members. See Suspending a DR group pair.
Presentation blocking provides protection
Disk presentation blocking is a feature that is similar to failsafe operation. See Failsafe mode.
Blocking can provide the following:
• Data consistency during a site failure–when a source and its destination virtual disk could be
simultaneously presented to different hosts.
• Protection in stretched-host clusters against host members accessing two copies of the same
data.
• Protection for boot-from-SAN servers against two hosts booting from the same boot image.
90 DR groups