HP XP P9500 Storage - Manual (Page 25)

When you create more pairs than the maximum initial copy setting, the pairs with priorities within
the maximum number specified run concurrently, while the pairs with priorities higher than the
maximum number wait. When one pair completes, a waiting pair begins, and so on.
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 “Specifying number of concurrent initial/resync copies” (page 49) to set the maximum initial
copies.
The Priority field is discussed in “Creating the initial copy ” (page 54) .
Disaster recovery considerations
You begin a disaster recovery solution when planning the Cnt Ac-J 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.
•
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 “Disaster
recovery operations ” (page 91) to become familiar with disaster recovery processes.
Host failover software
Host failover software is a critical component of any disaster recovery effort. When a primary
system fails to maintain synchronization of a Cnt Ac-J pair, the primary system generates sense
information. This information must be transferred to the remote site using the host failover software
for effective disaster recovery. RAID Manager provides failover commands that interface with
industry-standard failover products.
Disaster recovery considerations 25