HP XP RAID Manager Software - Manual (Page 28)

5 Pair operations
This chapter provides instructions for performing pair operations. All other Snapshot pair operations
are performed using RAID Manager.
Pair operations workflow
The operations workflow consists of the following:
•
Check pair status. Each operation requires a pair to have a specific status. You also check
status to insure than an operation completed successfully.
•
Create the pair, in which the V-VOL becomes a virtual duplicate of the P-VOL.
•
Split the pair, which creates a point-in-time Snapshot of the P-VOL in the V-VOL, allowing use
of the V-VOL by secondary applications.
•
Resume the pair, in which Snapshot data is discarded and the V-VOL is again a virtual copy
of the P-VOL.
•
Delete the pair, in which the pair relationship between the pair volumes is ended.
•
A pair can also be reverse resynchronized, restored, in which the P-VOL data is restored to
the point-in-time data of the last Snapshot.
Checking pair status
Each pair operation requires a specific status. Check pair status before performing an operation.
•
For instructions on checking status, see “Monitoring the system” (page 32) .
•
For the operations allowed for specific statuses, see “Pair status definitions” (page 32) .
Creating a pair
When a pair is created, the V-VOL becomes a virtual copy of the P-VOL. Updates to the P-VOL are
reflected in the V-VOL until the pair is split.
Prerequisite Information
•
The data pool and V-VOL for the new pair must created. See “Installation and configuration”
(page 25) for more information.
•
Review pair volume requirements in “Planning and design” (page 10) .
•
The pair volumes must be in SMPL status.
•
Use the same data pool for all pairs sharing a single P-VOL. For example, three pairs with
the same P-VOL must use the same data pool.
•
If data pool capacity exceeds the threshold when the paircreate command is issued, the
command is rejected and the pair is not created.
•
If you issue the paircreate command immediately after deleting previous Snapshot data, be
aware that the operation requires a longer time to complete.
•
The RAID Manager hide mode (-m noread) is not supported for S-VOLs (V-VOLs). If you specify
it, the paircreate completes normally but the hide mode is ignored.
•
When using an HP-UX host server, the Snapshot pair must be created before you issue the
command on the host to recognize the V-VOL device.
CAUTION: If a volume is recognized by the HP-UX host server, do not use the volume as a
V-VOL. Otherwise an error occurs and the host server may be terminated.
28 Pair operations