3PAR InForm® OS 2.3.1 CLI Administrator's Manual (320-200180 Rev B, February 2010)

7.9
Virtual Volume Types
InForm OS Version 2.3.1 3PAR InForm CLI Administrator’s Manual
7.6 Virtual Volume Types
There are three types of virtual volumes:
■ Fully-provisioned virtual volumes
■ Thinly-Provisioned Virtual Volumes (TPVVs)
■ Administrative Volumes
Administrative volumes are created by the system and are for system usage only.
Virtual volumes have three separate data components:
■ User space is the area of the volume that corresponds to the logical disk regions in the CPG
available to the host. The user space contains the user data and is exported as a LUN to the
host.
■ Snapshot space, also known as copy space, is the area of the volume that corresponds to
logical disk regions in the CPG containing copies of user data that changed since a snapshot
of the volume was created. The snapshot space contains the copy data.
■ Administration space, also known as admin space, is the area of the volume that
corresponds to logical disk regions in the CPG that track changes to the volume since a
snapshot was created. The administration space contains pointers to copies of user data in
the snapshot space. Administration space is managed by the system, not with the tools you
use to manage user and snapshot space.
You can increase the size of volumes, the amount of user space, and the amount of snapshot
space for volumes as the requirements increase. If the user space and snapshot space use all
available space, the 3PAR Virtual Copy feature’s copy-on-write operation will fail. To avoid
running out of user space, use TPVVs to automatically draw more user space from a CPG. The
InForm OS automatically reclaims unused snapshot from TPVVs and fully-provisioned virtual
volumes and returns the space to the logical disks.
For greater administrative flexibility, you can provision the virtual volume’s user space and
snapshot space from the same or different CPGs. If the virtual volume’s user space and
CAUTION: It is strongly recommended that you do not tamper with the admin
volumes.