System Guidelines For Creating Cpgs; Volume Types Associated With Cpgs - HP 3PAR StoreServ 7200 2-node Manual

In addition, volumes that draw from a CPG can only use the space available to that CPG based
on the CPG's logical disk parameters. For example, if you create a CPG that only uses logical
disks that belong to controller node 0, when the virtual volumes that draw from a CPG have filled
up all space available to that CPG based on it's logical disk parameters, the following will happen:
New writes to any TPVVs mapped to that CPG will return write failures.
Snapshot volumes mapped to the CPG may become invalid (stale), subject to the virtual copy
policy associated with the base volume. For base volumes with a no stale snapshots virtual
copy policy, new writes to the base volume will result in write failures.
For base volumes with a stale snapshots virtual copy policy, new writes will cause snapshot
volumes to become invalid (stale).
If the volumes that draw from a CPG reach the CPG's growth limit, the system generates
additional alerts to notify you that all logical capacity for the CPG has been consumed.

System Guidelines for Creating CPGs

Use the following guidelines to ensure maximum performance and optimal reliability in the volumes
supported by those logical disks:
To provide the highest availability, chunklets in the same RAID set should be from different
drive cages, and then different drive magazines.
Physical disks with fewer used chunklets should be used before physical disks with more used
chunklets.
Chunklets in the same row should be from different physical disks. In other words, a physical
disk should not appear twice in the same row.
Chunklets should belong to a disk that is connected through the primary path to the logical
disk's owner node.
The system should use as many physical disks as possible.
The load on all physical disks should be balanced.
The system should use the largest possible row size.
NOTE: The system may round up when creating logical disks to support virtual volumes and
CPGs, resulting in a discrepancy between the user-specified size or growth increment and the
actual space allocated to logical disks created by the system. For more information, see
Disk Size and RAID Types" (page

Volume Types Associated with CPGs

Depending on the products and features licensed for use on the system, after creating a CPG you
can create two types of base volumes that draw from the CPG's logical disk pool: Thinly Provisioned
Virtual Volumes (TPVVs) and fully provisioned virtual volumes. These two volume types draw from
the pool in different ways. For information about TPVVs, see
(page 8). For information about fully provisioned virtual volumes, see
Volumes" (page
38).
8).
"Thinly-provisioned Virtual Volumes"
"Fully-provisioned Virtual
System Guidelines for Creating CPGs
"Logical
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