Disaster Recovery Operations; Preparing For Disaster Recovery; File And Database Recovery Procedures; Switch Operations To The Secondary Site - HP XP P9500 User Manual

9 Disaster recovery operations

This chapter provides guidelines for performing disaster recovery operations. Also included are
disaster recovery procedures when Continuous Access Journal is configured with Continuous Access
Synchronous and Business Copy.

Preparing for disaster recovery

The major steps for preparing for disaster recovery are:
Identify the data volumes that you wand to back up for disaster recovery.
Pair the important volumes using Continuous Access Journal.
Establish file and database recovery procedures.
Install and configure host failover software between the primary and secondary sites.
The first two steps are the focus of this manual. The last two are discussed in this chapter. Also
covered here are recovery procedures for specific Continuous Access Journal cascade configurations.

File and database recovery procedures

When the primary or secondary system suspends a pair due to a disaster, the S-VOL may contain
in-process data due to a data set that may be open or transactions that have not completed. File
recovery procedures are necessary in such cases. These procedures should be the same as those
used for recovering a data volume that becomes inaccessible due to control unit failure.
Continuous Access Journal does not provide a procedure for detecting and retrieving lost updates.
To detect and re-create lost updates, you must check other current information (for example,
database log file) that was active at the primary site 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 secondary 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).
Remote copy and disaster recovery procedures are inherently complex. Consult your HP account
team on recovery procedures.

Switch operations to the secondary site

If a disaster or failure occurs at the primary site, the first disaster recovery activity is to switch host
operations to the secondary site. Executing the RAID Manager (RAID Manager) horctakeover
command enables business operations to be taken over by the secondary site.
The horctakeover command checks the pair status of S-VOLs and splits journals. Splitting the
pairs in the journals ensures consistency and usability in the S-VOLs.
If possible, the horctakeover command attempts to restore pairs to reverse P-VOLs and S-VOLs.
If the horctakeover command executes successfully, your business operations are taken over
to (or your business application is started at) the secondary site using the S-VOLs. For detailed
information about RAID Manager and horctakeover, see HP P9000 RAID Manager User
Guide.

Copy data back to the primary site

When the disaster recovery procedure is completed and host applications are running at the
secondary site, the next activity is to restore the primary site and re-establish the Continuous Access
Journal system for copying data from the secondary site to the primary site.
92 Disaster recovery operations