10 Disaster Recovery Operations; Preparing For Disaster Recovery; File And Database Recovery Procedures; Switch Operations To The Secondary Site - HP StorageWorks P9000 User Manual

10 Disaster recovery operations

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

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 Z.
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 Z 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 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 site when the disaster occurred.
The journal log file entries of most DBMS have the same system TOD clock information that is used
for I/O timestamps (when Timer Type = system). The Continuous Access Journal Z group consistency
time can be extremely useful when performing this detection and retrieval. (See Timer Type option
in "Register journal volumes in a journal" (page
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). You can also use the sense information with
system time stamp that is transferred via ERC.
Remote copy and disaster recovery procedures are inherently complex. Consult your HP account
team on recovery procedures.

Switch operations to the secondary site

The basic procedures for switching operations to the remote backup site are as follows:
1. If you need to perform an IPL of the secondary host system, delete SIMs and then perform the
IPL. When the IPL finishes, the S-VOLs are usually varied online. If the secondary volume is not
varied online, vary the volumes online.
If you do not need to perform an IPL of the secondary host system, insure that the S-VOLs are
varied online before continuing.
2. Check whether the restore journal includes an S-VOL with a pair status of Pending duplex or
Suspend (equivalent to SUSPOP in Business Continuity Manager).
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