HP XP P9500 Storage - Manual (Page 55)

6 Pair operations
This chapter provides prerequisite information and the instructions for performing Continuous Access
Synchronous Z operations.
Pair operations workflow
Basic Continuous Access Synchronous Z operations consists of the following.
•
Check prerequisites for each procedure.
•
Always check pair status. Each Continuous Access Synchronous Z operation requires the pair
to be in a specific status.
•
Create the pair, in which the R-VOL becomes a duplicate of the M-VOL.
•
Suspend the pair, which separates the M-VOL and R-VOL and allows read/write access to
the R-VOL if desired.
•
Resynchronize the pair, in which the R-VOL again mirrors the ongoing, current data in the
M-VOL.
•
Delete a pair
For disaster recovery procedures, see “Planning and procedures for disaster recovery” (page 74) .
Check pair status
Every Continuous Access Synchronous Z operation requires that the pairs have a specific status.
Before performing any operation, check pair status.
•
Find status requirements under the Prerequisites topics for each operation.
•
To view a pair’s current status in the GUI, or review status definitions, see “Monitor pair status”
(page 61) .
Create pairs
When you create the initial copy, all data in the M-VOL on the main system is copied to the R-VOL
on the remote system. The M-VOL remains available to the host for I/O operations.
Prerequisite information
The following information is provided to help you prepare for the Add Pair operation:
•
The initial copy is performed from the main system.
•
R-VOLs must be offline to all hosts.
•
You will select the main and remote volumes to be paired by individual volumes' CU and/or
LDEV numbers. You should have this information on hand.
•
Ports must be configured for Continuous Access Synchronous Z. See “Define port attributes”
(page 45) for more information.
•
The main and remote system must be configured for Continuous Access Synchronous Z. See
“Configure disk arrays and define logical paths” (page 46) for more information.
•
Stop Performance Monitor before performing the initial copy to avoid overloading with TCP/IP
traffic.
M-VOL Fence Level settings
The M-VOL Fence Level setting, which you specify during the Add Pair operation, determines
whether the host is denied access or continues to access the M-VOL when a Continuous Access
Pair operations workflow 55