HP StorageWorks Snapshot XP user guide (December 2005)

Snapshot XP user guide 23

1. If a volume is not assigned to a Snapshot XP pair, its status is SMPL.

2. Issue the paircreate command on the SMPL volume to create a Snapshot XP pair. When creating

the first pair for the P-VOL, the pair status changes to COPY. When the operation completes, the pair

status changes to PAIR. If you specify a volume that is already paired with one or more S-VOLs as the

P-VOL to create another pair, the pair status does not change to COPY. When the operation completes,

the pair status changes to PAIR.

NOTE:

• If you execute the paircreate command immediately after deleting the P-VOL’s last snapshot

data, it might take time to create a new pair.

• If the pool capacity exceeds the threshold when a Snapshot XP pair is in PAIR status, the pair

status changes to PFUL in RAID Manager. For more information, see the HP StorageWorks RAID

Manager XP User Guide.

•If you issue the paircreate command when the pool capacity exceeds the threshold, the

command is rejected and the pair cannot be created.

3. Issue the pairsplit command on the Snapshot XP pair in PAIR status to store the snapshot data in

the pool. When the operation completes, the pair status changes to PSUS.

NOTE: If the pool capacity exceeds the threshold when a Snapshot XP pair is in PSUS status, the

pair status changes to PFUS in RAID Manager. For more information, see the HP StorageWorks

RAID Manager XP User Guide.

4. To delete only snapshot data and leave the Snapshot XP pair, issue the pairresync command for the

PSUS or PFUS pair. During the operation, the pair status changes to COPY(RS).

To delete the Snapshot XP pair, issue the pairsplit-S command or use Command View XP or XP

Remote Web Console. During the operation, the pair status changes to SMPL(PD).

5. To restore the pair, issue the pairresync-restore command on the Snapshot XP pair in PSUS

status. After that, the snapshot data is written back to the P-VOL. During the operation, the pair status

changes to COPY(RS-R). When the operation completes, the pair status changes to PAIR.

6. A pool can contain only a predefined amount of data. If the total capacity of the snapshot data in the

pool exceeds the pool capacity, the pair status changes to PSUE. The pair status also changes to PSUE

when a failure occurs while restoring the pair or when the pool usage rate reaches 100 percent. The

pair status might change to PSUE when a failure occurs during a process other than restoring.

Whether the host can read and write the Snapshot XP pair’s P-VOL or S-VOL depends on the pair status.

Table 5 shows the relationship between the pair status and availability of host access.

Table 5 Whether hosts can access P-VOLs and S-VOLs

Pair status P-VOL S-VOL

Read Write Read Write

SMPL OK OK — —

COPY OK OK No No

PAIR/PFUL OKOKNoNo

PSUS/PFUSOKOKOKOK

SMPL(PD) OK OK No No

COPY(RS) OK OK No No

COPY(RS-R) No No No No

PSUE OK

1. If the pair status changes to PSUE because a failure occurred during the restoration, the host cannot access that pair.

No No