HP XP P9500 Storage - Manual (Page 41)

Prerequisite information for creating pairs
•
Make sure that your volumes are set up for pairing. For more information, see “Planning pair
volumes” (page 13) .
•
Volumes should be in SMPL status. However, for L1 and L2 pairs, check the status. For more
information on the L1 and L2 permitted statuses, see
“Status for L1, L2 pairs and operations
permitted” (page 55) .
•
When creating an L1 pair and an L2 pair at the same time, specify Non Split as the Split Type.
Doing this prevents failure, since using another split type can result in the split operation for
the L2 pair to begin before the pair status changes to PSUS.
•
If the P-VOL is already paired with other S-VOLs, before creating the new pair, check the
permitted status of existing S-VOLs. For more information, see
“Status of unaffected S-VOLs,
operations permitted ” (page 57) .
•
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 you create a pair, the S-VOL’s LDEV is allocated to the same processor blade to which
the P-VOL’s LDEV is allocated.
•
The paircreate operation overwrites all existing data on the S-VOL. The user is responsible for
backing up data on the S-VOLs before creating pairs.
•
If you use DKAs supporting encryption, you can create a BC pair by using an encrypted
volume and a non-encrypted volume. For example, you can create the pair specifying an
encrypted volume as the P-VOL and a non-encrypted volume as the S-VOL. In this case, data
in the encrypted P-VOL becomes non-encrypted data in the S-VOL.
•
In the Create Pairs wizard, specify pair configuration settings that require additional
explanation.
For more information on setting up pair configurations, see “On creating L1 and L2 pairs with
different topologies” (page 41) .
•
If you are using one of its volumes as an FS P-VOL, first create the BC pair.
If an MU number is not available, complete the following:
1.
Delete the FS pair that has an MU number between 0 and 2.
2. Create the BC pair.
3. Create the FS pair.
On creating L1 and L2 pairs with different topologies
You begin the Create Pairs wizard by specifying L1 and L2 pair topology in the Select Pair
Configuration window. Though you may be performing the operation for more than one P-VOL,
you specify pair topology only once, and this topology applies to all P-VOLs in the operation.
However, you can change L1 and L2 pair configurations that do not match the specified
configuration later in the Create Pairs wizard. This is also true when you create a new pair using
an existing P-VOL with an existing configuration.
To change L1 and L2 pair configuration, you begin by setting the topology for the pair with the
largest topology. The following figure shows an example of the P-VOL with the largest topology,
of all the pairs being created in an operation.
Pair creation 41