HP XP7 Storage - Manual (Page 96)

Continuous Access Synchronous Z does not provide a procedure for detecting and retrieving lost
updates. To detect and recreate lost updates, you must check other current information (for example,
database log file) that was active at the primary system when the disaster occurred.
The detection and retrieval process can take some time. Your disaster recovery scenario should
be designed so that detection and retrieval of lost updates is performed after the application has
been started at the remote site.
You should prepare for file and database recovery using files for file recovery (for example,
database log files that have been verified as current). You can also use the sense information with
system time stamp that is transferred via ERC.
CSUSPEND/QUIESCE TSO command
See the IBM documents SG24 2595, SC35 0355, and SC35 0169 for important information
about the optional QUIESCE parameter for the CSUSPEND TSO command.
The QUIESCE option of the CSUSPEND command has been disabled by APAR OW15247 or
APAR OW15248. Refer to either of these APARs and the latest IBM PPRC documentation for
detailed information about the QUIESCE option of the CSUSPEND command. Please check with
your HP account team before using the CSUSPEND command with the QUIESCE option to suspend
Cnt Ac-S Z pairs on XP7 storage systems. If the CSUSPEND command with the QUIESCE option
is issued to certain volumes (for example, active SPOOL, PAGE, or CATALOG datasets, active
SYSRES volume), the attached hosts may enter a deadlock condition and may require a storage
control IML to correct the condition.
IEA494I system console message
The IEA494I message is recommended as a trigger for automation over the IEA491E message,
because the IEA494I message is reported to all attached MVS hosts each time the P-VOL pair status
changes, whereas the IEA491E message is reported to only one host system.
Switching operations to the remote site
If a disaster or failure occurs at the local site, the first disaster recovery activity is to switch your
operations to the remote site. S-VOLs are recovered individually based on the pair status and P-VOL
fence level information for each pair.
You can swtch operations to the remote site either by deleting pairs, then reestablishing them when
recovery is completed; or by not deleting pairs. Both methods are presented below.
Procedure 33 To switch operations to the remote site by deleting pairs
1. Record the pair status and fence level of each S-VOL.
2. Analyze the consistency of the S-VOLs, based on pair status and P-VOL fence level setting.
See
“Checking S-VOL consistency with the P-VOL” (page 97) .
3. Perform file recovery as needed.
4. Split all pairs from the S-VOLs using one of the following commands:
•
RAID Manager pairsplit
•
BCM YKSUSPND
•
PPRC CSUSPEND
5. Release all pairs using one of the following commands:
•
RAID Manager pairsplit -S
•
BCM YKRECOVER
•
PPRC CRECOVER
If you are not using these tools, connect to each secondary system with Remote Web Console
to split and release the pairs.
96 Disaster recovery