3PAR InForm® OS 2.2.4 Concepts Guide (320-200085 Rev B, March 2009)

8.5
Virtual Volume Types and Variations
InForm OS Version 2.2.4 3PAR InForm OS Concepts Guide
8.7 Virtual Volume Types and Variations
There are three distinct types of virtual volumes:
■ Base volumes
■ Physical copies
■ Virtual copies
In addition, base volumes have two variations for allocating space on demand:
■ Thinly provisioned virtual volumes (TPVVs)
■ Commonly provisioned virtual volumes (CPVVs)
8.7.1 Base Volumes
Base volumes form the root of all virtual and physical copy operations. When snapshot
functionality is not licensed for use on a system, base volumes are the only type of virtual
volume that you can create and export.
Base volumes have three components, two of which are only significant when snapshot
functionality is licensed for use on the system:
■ User space, the area of the volume that corresponds to logical disk regions holding data
seen by hosts to which the volume is exported as a LUN. These logical disk regions hold the
volume's user data. These logical disks are either created automatically during the creation
of the volume, or are allocated from a common provisioning group (CPG).
■ Snapshot data space, also known as copy space, corresponds to logical disk regions holding
data that has changed since a snapshot (or point-in-time copy) of a volume was created.
These logical disk regions hold the volume's copy data.
■ Snapshot administration space, also known as admin space, corresponds to logical disk
regions that track changes to the volume since a snapshot was created. These logical disk
regions hold pointers to the snapshot data space that contains the latest changes made to a
volume.