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

16.3
Dynamic Optimization
InForm OS Version 2.3.1 3PAR InForm CLI Administrator’s Manual
■ Volume layout changes after hardware upgrades. Existing virtual volumes only take
advantage of resources that were present at the time of volume creation. When an InServ
Storage Server is upgraded by adding nodes, cages, or disks, the original volume and logical
disk layouts may no longer be optimal. Changing the layout of a virtual volume enables
volumes to take full advantage of new system resources.
By default, Thinly-Provisioned Virtual Volumes (TPVVs) and their underlying Common
Provisioning Groups (CPGs) dedicate space from all available resources as they grow, both
from pre-existing and new drive capacity resources. This natural expansion capability of
TPVVs reduces the need for Dynamic Optimization to change the layout of TPVVs after
adding disks.
■ Volume RAID level changes. Since different RAID levels have varying capacity
requirements and offer differing degrees of performance relative to each other, you may
desire to convert volumes from one RAID type to another when system requirements
change. Volume RAID level changes are non-disruptive.
■ Volume availability level changes. 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 magazine-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 changes. In addition to non-disruptively altering RAID and
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 the volume was created.
Each Dynamic Optimization operation is treated as a task. For information about system tasks,
see Chapter 13, Managing Tasks. Eight Dynamic Optimization tasks can run simultaneously. If
more than eight Dynamic Optimization tasks are started, task number nine and above are
queued until one or more of the initial eight tasks are completed.