HP StorageWorks XP Remote Web Console Software - Manual (Page 16)

If you specify a volume which is already paired with one or more S-VOLs as the P-VOL to create
another pair, the pair status will not change to COPY, and the pair status will change to PAIR
when the operation completes.
Notes :
• If you execute the paircreate command immediately after deleting the last snapshot data of
the P-VOL, it may take time to create a new pair.
• If the pool capacity exceeds the threshold when an XP Snapshot pair is in PAIR status, the
pair status changes to PFUL in RAID Manager. For details, see the HP StorageWorks XP RAID
Manager User’s Guide.
• If you issue the paircreate command when the pool capacity exceeds the threshold, the
command will be rejected and the pair cannot be created.
3. Issue the pairsplit command on the XP Snapshot 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 an XP Snapshot pair is in PSUS status,
the pair status changes to PFUS in RAID Manager. For details, see the HP StorageWorks XP
RAID Manager User’s Guide.
4. To delete only snapshot data and leave the XP Snapshot pair, issue the pairresync command to
the PSUS or PFUS pair. During the operation, the pair status changes to COPY(RS).
To delete the XP Snapshot pair, issue the pairsplit-S command or use Remote Web Console.
During the operation, the pair status changes to SMPL(PD).
5. Issue the pairresync-restore command on the XP Snapshot pair in PSUS status to restore the pair.
After that, the snapshot data will be 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 usage rate
of the pool reaches 100 percent. The pair status may change to PSUE when the failure occurs
during a process other than restoring.
Whether the host can read and write the P-VOL or S-VOL of an XP Snapshot pair depends on the status
of the pair. Table 2 on page 16 shows the relationship between the pair status and the availability of
the host access.
Table 2 Whether Hosts Can Access P-VOL and S-VOL
Pair Status P-VOL S-VOL
Read Write Read Write
SMPL OK OK - -
COPY OK OK No No
PAIR/PFUL OK OK No No
PSUS/PFUS OK OK OK OK
SMPL(PD) OK OK No No
COPY(RS) OK OK No No
COPY(RS-R) OK OK No No
PSUE OK* OK* No No
Note* : If the pair status changes to PSUE because of a failure during restoration, the host cannot
access that pair.
Caution: If the host computer uses application software to monitor the volumes of the XP Snapshot pairs,
problems such as an abnormal end may occur. For example, since an S-VOL whose status is not PSUS
(or PFUS) rejects the access from the host, problems may occur on the monitoring application software
whose access is rejected. In addition, if the host computer connects to more than one port, problems may
About XP Snapshot Operations 16