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

19.2
3PAR InForm OS Concepts Guide InForm OS Version 2.2.4
of this natural expansion, a system with TPVVs reduces the need for Dynamic Optimization
to re-layout volumes after adding disks. Note that capacity dedicated to TPVVs and CPGs
prior to adding new node pairs to a system is not "tunable" into the capacity associated
with the subsequently added node pairs. If, in rare circumstances, this becomes necessary,
contact your 3PAR Technical Account Manager (TAM).
■ Volume RAID level change. Since different RAID levels have varying capacity requirements
and offer differing degrees of performance relative to each other, at some point it may be
desirable to convert volumes from one RAID type to another. Volume RAID level change
enables you to transform volume RAID levels non-disruptively.
■ Volume availability level change. The availability of a virtual volume determines its level of
fault tolerance. For example, a volume with a cage-level availability can tolerate the failure
of a drive cage because its RAID sets use chunklets from different drive cages. A volume
with a mag-level availability can tolerate the failure of a drive magazine because its RAID
sets use chunklets from different magazines. As applications and business requirements
change, it may be desirable to non-disruptively alter the availability characteristics of
existing virtual volumes.
■ Volume service level change. In addition to non-disruptively altering RAID and/or
availability levels for a given volume or volumes, it may also be useful to change volume
parameters such as the disk filtering parameters applied when creating a volume.
■ Dynamically modify TPVV. The tunetpvv command allows the RAID and Availability
characteristics of an exiting TPVV to be dynamically modified.
For instructions on using Dynamic Optimization, refer to the 3PAR InForm OS CLI
Administrator’s Manual.