HP 3PAR InForm OS 3.1.1 Concepts Guide

Compacting a CPG allows you to reclaim space from a CPG that has become less efficient in
space usage from creating, deleting, and relocating volumes. Compacting consolidates logical
disk space in CPGs into as few logical disks as possible. Compacting CPGs can be performed
with both the HP 3PAR InForm OS Command Line Interface (CLI) and the HP 3PAR InForm
Management Console. Refer to the HP 3PAR InForm OS CLI Administrator’s Manual and the HP
3PAR InForm Management Console Online Help for instructions on how to perform this task.
Reclaiming Unmapped Logical Disk Space from Volumes
When multiple identical virtual volumes are created as a result of a single volume creation operation,
the underlying logical disks that support those volumes are shared by the volume group. If several
of the members of that volume group are later deleted, the underlying logical disks may become
less efficient in the usage of space. One or more logical disks shared by the volume group may
have only a small portion of their regions mapped to existing virtual volumes. However, their
unused regions are not available to the system for use in creating new logical disks. Compacting
the logical disk regions mapped to these volumes may recover and free logical disk space.
Compacting logical disks can only be performed with the HP 3PAR InForm Command Line Interface
(CLI). Refer to the HP 3PAR InForm OS CLI Administrator’s Manual for instructions on how to perform
this tasks.
You can use the optional HP 3PAR Dynamic Optimization Software feature to configure volumes
to use space more efficiently. To learn about tuning volumes for optimal performance, see “Enhanced
Storage Applications” (page 53).
Automatically Reclaiming Unused Snapshot Space from Volumes
The InForm OS automatically reclaims unused snapshot and administration space from
Thinly-Provisioned Virtual Volumes (TPVVs) and fully-provisioned virtual volumes and returns the
space to the LDs. The system examines the snapshot and administration space for large areas of
unused space. The identified areas are unmapped from the corresponding LD regions and the
space is returned to the LDs.
Manually Reclaiming Unused Snapshot Space from Volumes
You cannot manually remove snapshot and administration space from a Thinly-Provisioned Virtual
Volume because the InForm OS automatically removes any unused space.
Reclaiming dormant snapshot and administration space from a fully-provisioned virtual volume and
returning the space to the LD can only be performed when the volume is not exported to a host,
and if there are no snapshots of the volume. Creating physical copies of the volume does not
prevent you from reclaiming space.
You can reclaim snapshot space from a virtual volume with both the HP 3PAR InForm Command
Line Interface (CLI) and the HP 3PAR InForm Management Console. Refer to the HP 3PAR InForm
OS CLI Administrator’s Manual and the HP 3PAR InForm Management Console Online Help for
instructions on how to perform this task.
Deleted Volume’s Snapshot Space
The unused space associated with deleted snapshots of Thinly-Provisioned Virtual Volumes (TPVVs)
and fully-provisioned virtual volumes is automatically returned to the pool of logical disks used by
the CPG.
52 Reclaiming Unused Space