HP StorageWorks XP24000 Continuous Access Software User and Reference Guide, v01 (T5278-96002, June 2007)

Switching Opera
tions to the Remote Site
If a disaster or
failureoccurs atthe primarysite, the first disaster recovery activi ty is to switch your
operations to the secondary s ite. The Continuous Access Synchronous S-VOLs are recovered individually
based on the pair status and P-VOL fence level information for each pair. The Continuous Access
Asynchronous S
-VOLs are recovered based on the pair status and co nsistency status (at the RCU).
The basic procedures for switching operations to the remote backup site are :
1. Record the pair status and fence level of each Continuous Access Synchronous S-VOL.
Record the pair status and consistency status of each Continuous Access Asynchronous S-VOL
(displayed on
ly at the RCU). Suspended Continuous Access Asynchronous S-VOLs with a
consistency status of group are consistent with the other S-VOLs in the group and can be used
fordisasterrecovery.
2. Analyze the currency of the Continuous Access Synchronous S-VOLs (see
“Analyzing t
he
Currency of Continuous Access Synchronous S-VOL s” on page 130)
and the consi
stency of the Continuous Access Asynchronous S-VOLs (see
“Analyzing the Consistency of Continuous Access Asynchronous S-VOLs”onpage131).
3.
Perform file
recovery as need ed (see “File and Database Recovery Procedures” on page 129) .
4. At the remote site, connect to each RCU, and release all Continuous Access Synchronous pairs.
For Continuous Access A synchronous pairs, release all consistent pairs in a group at the same
time using the pairsplit-S command with the C/T delete range option. This option prevents you
from accidentally using inconsistent pairs for disaster recovery.
Caution: Once an S-VO L changes to simplex, you cannot distinguish it from a non-Continuous
Access si
mplex volume. The Continuous Access Asynchronous consistency status is also
discarded when the pair is released.
5. If necessary, use the volume manager to change the volume labels of the S-VOL s.
6. Make sure that all required file recovery procedures have been completed before varying the
S-VOLs o
nline.
7. At this point, you may start critical applications at the remote site with the previous S-VOLs taking
the
place of their P-VOLs.
Analyzing the Currency of Continuous Access Synchronous S-VOLs
Table 24 on page 1 31 shows how to determine the currency of a Continuous Access Synchronous S-VOL
based on its pair status and P-VOL fence level setting. For Continuous Access Synchro nous pairs with a
P-VOL fence level setting of Never, further analysis will be required to determine the currency of these
S-VOLs. The currency of these S-VOLs can be determined by using the sense information transferred via
the
host failover, or by comparing the contents of the S -VOL with other files which are confirmed to
be
current (for example, database log fi les). These S-VO Ls should be recovered using the files which
are confirmed to be current.
Note: Actual data recovery must be d one using recovery point data in the database redo log.
130 Usage Scenarios