HP P6000 Continuous Access Implementation Guide (T3680-96431, August 2012)

Table 4 Default DR group write history log placement
XCS 6.000 or later
XCS 09003000 or later
VCS, XCS 6.000 or earlierArray status
Use the defined disk group.Use the defined disk group.The array contains one defined disk
group.
Use the online disk group.Use the near-online disk group.The array contains one near-online disk
group and one online disk group.
Use the near-online disk group
containing the most average free
Use the near-online disk group
containing the most average free
The array contains only multiple
near-online disk groups.
space based on the number of DRspace based on the number of DR
group logs assigned to the disk
groups.
group logs assigned to the disk
groups.
Use the online disk group containing
the most average free space based
Use the online disk group containing
the most average free space based
The array contains only multiple online
disk groups.
on the number of DR group logs
assigned to the disk groups.
on the number of DR group logs
assigned to the disk groups.
Use the online disk group containing
the most average free space based
Use the near-online disk group
containing the most average free
The array contains one or more
near-online disk groups, and one or more
online disk groups. on the number of DR group logsspace based on the number of DR
assigned to the disk groups. If allgroup logs assigned to the disk
online disk groups are full orgroups. If all near-online disk groups
inoperative, use a near-online diskare full or inoperative, use an online
group based on the same space
criteria.
disk group based on the same space
criteria.
Planning replication relationships
One array can have replication relationships with multiple arrays. This section describes creative
ways to optimize your remote replication resources.
Bidirectional replication
In bidirectional replication, an array can have both source and destination virtual disks that will
reside in separate DR groups. (One virtual disk cannot be both a source and destination
simultaneously.) For example, one DR group can replicate data from array A to array B, and
another DR group can replicate data from array B to array A. Bidirectional replication enables
you to use both arrays for primary storage while they provide disaster protection for another site.
When using bidirectional replication: disk groups on arrays in a bidirectional relationship should
be appropriately sized for the load they will be carrying. Consider the bandwidth as two
unidirectional flows, and add the two flows together to determine the bandwidth requirements.
For other considerations related to bidirectional replication, see the HP Enterprise Virtual Array
Configuration Best Practices White Paper for your array model.
46 Planning the array configuration