Manual

E Pair operations (secondary window)
This appendix provides instructions for performing pair operations using the previous RWC GUI,
which opens in a secondary window.
Pair operations workflow
A typical pair-operations workflow follows:
• Check pair status. Each operation requires a pair to have a specific status. You also check
pair status to ensure that an operation completed successfully.
• Create the pair, in which the T-VOL becomes a duplicate of the S-VOL. You can create the
pair and immediately split it so that you can have instant access to the T-VOL.
• Split the pair, which separates the source and target volumes and allows use of T-VOL data
by secondary applications.
• Resynchronize the pair, in which the T-VOL is again updated from the S-VOL.
• Delete the pair, in which the pair relationship between the pair volumes is ended, though the
data remains.
Check pair status
Every pair operation requires the pair to have a specific status. When you want to perform a pair
operation, check pair status to ensure that you can proceed successfully.
• For pair status definitions and instructions for finding pair status, see “Monitoring the system
” (page 49).
Creating pairs
When you create the initial copy, data in the S-VOL is copied to the T-VOL. During the operation,
the S-VOL can receive updates from the host. When the initial copy is completed, the updated data
in the S-VOL—differential data—is copied to the T-VOL periodically (update copy).
You can create the pair and immediately split it so that you can have instant access to the T-VOL.
For more information about creating and splitting pairs, see “Splitting pairs, creating and splitting
pairs” (page 129).
Prerequisite information
• Make sure that your volumes are set up for pairing. For more information, see “Planning pair
volumes” (page 15).
• If the S-VOL is used with another pair, the pair status of the existing pairs must be DUPLEX.
• If the S-VOL is not used with another pair, the S-VOL and T-VOL must not be assigned to a
pair (SIMPLEX status).
• Because pair creation affects performance on the host, observe the following:
Create a pair when I/O load is light.◦
◦ Limit the number of pairs that you create simultaneously.
• When a pair is created, the T-VOL’s LDEV is allocated to the same processor blade to which
the S-VOL’s LDEV is allocated.
WARNING! The BC Z paircreate operation overwrites all existing data on the T-VOL. The user
is responsible for backing up data on the T-VOLs before creating BC Z pairs.
1. In the RWC, click Actions > Local Replications > BC Z/FC Z > Pair Operation.
2. Change to Modify mode by clicking the icon.
Pair operations workflow 127