HP XP7 Storage - Manual (Page 31)

If you perform a pair operation for multiple pairs (for a specific kind of data, for example), and
then perform another operation for multiple pairs (for another specific kind of data, for example),
the pairs in the first operation are completed in the order of their assigned priorities. The system
begins processing pairs in the second set when the number of pairs left in the first set drops below
the maximum number of initial copy-setting. This is shown in the following example.
See the step for Priority in the procedure in “Creating the Cnt Ac-J Z initial copy ” (page 68) .
Disaster recovery considerations
You begin a disaster recovery solution when planning the Cnt Ac-J Z system. The following are the
main tasks for preparing for disaster recovery:
•
Identify the data volumes that you want to back up for disaster recovery.
•
Pair the identified volumes using Cnt Ac-J Z.
•
Establish file and database recovery procedures.
•
Install and configure host failover software error reporting communications (ERC) between the
primary and secondary sites.
For more information on host failover error reporting, see the following topic. Also, review “Cnt
Ac-J Z disaster recovery operations ” (page 105) to become familiar with disaster recovery processes.
Error reporting communications (ERC)
Error reporting communications (ERC) transfers information between host processors at the primary
and secondary sites. It is a critical component of any disaster recovery effort. You can configure
ERC using channel-to-channel communications, NetView technology, or other interconnect
technologies, depending on your installation requirements and standards. Neither Cnt Ac-J Z nor
Remote Web Console provides ERC between the primary and secondary sites.
When Cnt Ac-J Z is used as a data migration tool, ERC is recommended but not required. When
it is used as a disaster recovery tool, ERC is required to ensure effective disaster recovery operations.
When a pair is suspended due to an error condition, the primary system generates sense information
which results in an IEA491E system console message. This information should be transferred to
the local site via the ERC for effective disaster detection and recovery.
Disaster recovery considerations 31