HP XP Business Copy Software - Manual (Page 81)

Table 35 Specifications of Consistency Groups
Descriptions Items
A number (0−127) is assigned to each consistency group. You can specify a consistency
group number when you create XP Business Copy pairs. If you do not specify a number,
the storage system assigns a number automatically. Use the Volume List of the Pair
Operation window to view the default consistency group numbers.
You can configure up to 128 consistency groups in a storage system, including
ShadowImage for Mainframe consistency groups and XP Snapshot consistency groups.
Consistency group number
You can define up to 8,192 XP Business Copy pairs in a consistency group. However,
you should count LUSE volumes that contain n LDEVs as n volumes. For further information
on LUSE volumes, see the HP StorageWorks XP24000/XP20000 LUN Expansion User
Guide.
NOTE: XP Business Copy pairs, ShadowImage for Mainframe pairs, and XP Snapshot
pairs cannot co-exist in the same consistency group.
Number of pairs
Consistency groups have the following restrictions:
•
L1 and L2 cascade pairs cannot be defined if they share the same node volume in a consistency
group. If these pairs are specified within the same consistency group, the paircreate command
will be rejected.
•
Do not mix pairs created with the At-Time Split operation and pairs not created with the At-Time
Split operation within the same group, as defined in the RAID Manager configuration file. If
you mix these two types of pairs, the pairsplit operation may terminate abnormally or the
S-VOLs of the P-VOLs in the same consistency group may not be correctly created when the
pairsplit request is executed.
To enable the At-Time Split function using RAID Manager, follow these steps:
1. Edit the RAID Manager configuration definition file so that the XP Business Copy pairs belong
to the same consistency group.
2. Execute the RAID Manager paircreate command, specifying the option for using the At-Time
Split function.
The XP Business Copy pairs for the At-Time Split function are created.
3. Execute the pairsplit command using RAID Manager.
Data contained in the P-VOLs when the pairsplit command executes are copied to S-VOLs.
If the At-Time Split option is enabled, the data in all P-VOLs (in the same consistency group) is
created in the corresponding S-VOLs at the time when the pairsplit request is received by the storage
system.
If the At-Time Split option is disabled, the pairsplit operation does not ensure that S-VOLs will be
created from P-VOLs in the same consistency group. The At-Time Split option is disabled if you
perform XP Business Copy pair operations from the Remote Web Console computer on the XP
Business Copy At-Time Split pairs created by RAID Manager.
For detailed information, see the HP StorageWorks RAID Manager User Guide.
If the At-Time Split function using RAID Manager fails, the following problems will occur:
•
When the pairsplit operation by RAID Manager ends abnormally, all the XP Business Copy
pairs in the same consistency group will be suspended (status = PSUE).
•
When the host server is down or has failed, a consistency group with no XP Business Copy
pairs may be defined. If you execute the paircreate command with the At-Time Split option
Splitting Pairs 81