HP 3PAR InForm OS 3.1.1 CLI Administrator's Manual

• Number of CPGs in the system.
• Number of volumes associated with those CPGs.
• Anticipated growth rate of the volumes associated with the CPGs.
CAUTION: Use caution in planning CPGs. The system does not prevent you from setting growth
warnings or growth limits that exceed the amount of currently available storage on a system. When
volumes associated with a CPG use all space available to that CPG, any new writes to TPVVs
associated with the CPG will fail and/or snapshot volumes associated with the CPG may become
invalid. Invalid volumes do not handle write failures gracefully and may produce unexpected
failures.
CAUTION: Do not allow volumes that draw from a CPG to exceed the CPG's growth limit.
Exceeding the CPG growth limit can invalidate snapshot volumes.
NOTE: By default, the growth warning and growth limit are set to none, which effectively disables
these safety features.
NOTE: Refer to the HP 3PAR InForm OS Messages and Operator’s Guide for additional
information about specific alerts. Managing alerts is described in “Managing Events and Alerts”
(page 115).
System Guidelines for Creating Common Provisioning Groups
When you use the advanced parameters for logical disk creation, use the following guidelines to
ensure maximum performance and optimal reliability in the volumes supported by those logical
disks:
• Chunklets in the same RAID set should be from different drive magazines or drive cages.
• Chunklets in the same row should be from different physical disks. In other words, a physical
disk should not appear twice in the same row.
• Chunklets should belong to a disk that is connected through the primary path to the logical
disk’s owner node.
• The growth increment is limited to 40 chunklets.
• The system should use as many physical disks as possible.
• The load on all physical disks should be balanced.
• The system should use the largest possible row size.
Common Provisioning Group CLI Commands
Use the following CLI commands to manage Common Provisioning Groups (CPGs):
• showcpg - display CPGs in the system.
• createcpg - create CPGs.
• setcpg - modify existing CPGs
• compactcpg - consolidate logical disk space in CPGs into as few logical disks as possible.
• removecpg - remove CPGs from the system or remove specific logical disks from CPGs.
82 Managing CPGs and Virtual Volumes