HP StorageWorks XP Remote Web Console Software - Manual (Page 203)

9 Performing Disaster Recovery Operations
This chapter describes how to determine the best approach for disaster recovery. The user should
anticipate and plan for all types of failures and disasters.
•
“Preparing for Disaster Recovery” (page 203)
•
“Recovering from a Disaster in a 3DC Cascading Configurationof XP Continuous Access
Journal and XP Continuous Access Synchronous” (page 209)
•
“Recovering from Primary Site Disaster in a 3DC Multi-Target Configuration” (page 210)
•
“Recovering from Primary Site Failures in 3DC Multi Target Configuration of XP Continuous
Access Journal and XP Continuous Access Synchronous (When Delta Resync Operation Is
Performed)” (page 211)
Preparing for Disaster Recovery
The type of disaster and the status of the XP Continuous Access Journal volume pairs determines
the best approach for disaster recovery. Unfortunately, some disasters are not so orderly and
involve intermittent or gradual failures occurring over a longer period of time.
The major steps in preparing for disaster recovery are:
1. Identify the journal groups and data volumes that contain important files and data for disaster
recovery.
2. Install the Remote Web Console computer and XP Continuous Access Journal hardware and
software, and establish XP Continuous Access Journal operations for the journal groups and
data volumes identified in step 1.
3. Establish file and database recovery procedures. These procedures should already be
established for recovering data volumes that become inaccessible due to some failure.
4. Install and configure host failover software between the primary and secondary sites.
File and Database Recovery Procedures
When the primary or secondary storage system suspends an XP Continuous Access Journal pair
due to a disaster, the secondary data volume may contain in-process data. A data set could be
open or transactions may not have completed. Therefore, you need to establish file recovery
procedures. These procedures should be the same as those used for recovering a data volume that
becomes inaccessible due to a control unit failure.
XP Continuous Access Journal does not provide any 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. Since this
detection/retrieval process can take a while, your disaster recovery scenario should be designed
so that detection/retrieval of lost updates is performed after the application has been started at
the secondary site.
You should prepare for file and database recovery by using files for file recovery (for example,
database log files which have been verified as current). See
“Recovering a Pinned Track” (page 195)
for information on recovering a pinned track on an XP Continuous Access Journal volume.
Important: Remote copy and disaster recovery procedures are inherently complex. Consult your
HP service representative on recovery procedures.
Switching Operations to the Secondary Site
If a disaster or failure occurs at the primary site, the first disaster recovery activity is to switch your
operations to the secondary site. Executing the horctakeover command of RAID Manager on
Preparing for Disaster Recovery 203