HP StorageWorks Continuous Access XP user guide for the XP10000/XP12000 (December 2005)

104 Continuous Access XP for the XP10000/XP12000
4. Monitor the progress of initial copy operations and status of pairs on the Pair Operation tab of the
Continuous Access XP main pane. Refresh the tab as needed. When the status changes from COPY to
PAIR, the P-VOL and S-VOL are identical and synchronized.
5. If you are not using RAID Manager commands and host software to complete the migration, use the
following procedure to stop using P-VOLs and switch to S-VOLs:
a. Stop all host updates to P-VOLs.
b. When all update activity to P-VOLs stops, connect to the MCU, click the correct CU image, and
delete Continuous Access XP volume pairs (see ”Deleting Continuous Access XP volume pairs
(Pairsplit-S)” on page 99).
c. If P-VOLs and S-VOLs are attached to the same host, vary P-VOLs offline, and vary S-VOLs online.
P-VOLs and S-VOLs have the same volume labels and cannot be online to the same hosts at the
same time.
d. To keep volumes synchronized, establish the same Continuous Access XP pairs in the reverse
direction using the No Copy initial copy option (see ”Continuous Access XP initial copy and pair
options of the Paircreate pane” on page 93). If the original P-VOLs are temporarily unavailable for
update copy operations, split the new pairs (pairsplit-r) so the new MCU tracks changes.
e. Start applications with S-VOLs. When the original P-VOLs become available, resume pairs using the
Pair List (Pairresync) pane (see ”Resuming Continuous Access XP volume pairs (Pairresync)” on
page 97).
Point-in-Time data duplication using Continuous Access XP Asynchronous
Use Continuous Access XP Asynchronous (Continuous Access XP Async) to make Point-in-Time (PiT)
duplicates of groups of volumes. Use the Continuous Access XP Async Group and Drain pairsplit-r options
together to create a PiT copy, relative to an application, of an entire Continuous Access XP Async
consistency group of volumes.
1. Stop all host updates to all Continuous Access XP Async P-VOLs in the group.
2. After all P-VOL updates are complete, split the Continuous Access XP Async group using the Group and
Drain pairsplit-r options. If you are splitting the group at the main site, issue the pairsplit-r/group
command to one P-VOL in the MCU. If you are splitting the group at the remote site, issue the
pairsplit-r/group command to one S-VOL in the RCU.
The copy pending timeout setting for the group determines maximum amount of time the
pairsplit-r/drain operation can take (see previous description of Drain).
3. When the status of all Continuous Access XP Async pairs in the group changes to PSUS, the duplicate
set of volumes is complete. If needed, restart the application at the main site.
Powering off and on Continuous Access XP components
You are responsible for controlling power-off activities for disk arrays involved in Continuous Access XP
operations. If you need to power off the disk array, call your HP representative or HP technical support for
assistance. The following sections provide instructions for performing planned outages of Continuous
Access XP components.
If power is removed from an MCU while Continuous Access XP operations are in progress, Continuous
Access XP pairs are not affected, but update sequence consistency of Continuous Access XP Async groups
at the RCU may be affected (see ”Planned outage of MCUs” on page 105 for further information). When
power is restored to an MCU, the MCU communicates with its RCUs to confirm the pair status of the
S-VOLs. Ensure that Continuous Access XP communications are fully restored (all paths have normal status)
before beginning I/O operations to P-VOLs. If the MCU accepts a write I/O operation for a P-VOL before
this confirmation is complete, the MCU suspends the pair and changes the status of the P-VOL to
suspended-by RCU (the MCU cannot change the pair status of the S-VOL).
If power is removed from an RCU or remote copy connection while Continuous Access XP operations are in
progress, the MCU detects the communications failure, suspends all affected pairs, and generates SIMs
reporting the failures. The MCU changes the status of P-VOLs to suspended-by RCU, but cannot change the
status of S-VOLs.
If an MCU or RCU is powered off and its backup batteries are fully discharged while Continuous Access XP
pairs are suspended, the P-VOL and S-VOL cylinder maps are not retained. In this unlikely case, the MCU