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

10.3
Precautions and Planning
InForm OS Version 2.2.4 3PAR InForm OS Concepts Guide
10.2.1 Growth Increments, Warnings, and Limits
When creating a CPG, set a growth increment and an optional growth warning and growth
limit to restrict the CPG's growth and maximum size. Depending on the products and features
licensed for use on a system, you can then create several types of volumes that draw space
from the CPG's logical disk pool as needed.
It is important to plan the CPG's growth increment, growth warning, and growth limit
carefully and then continue to monitor the CPG closely over time.
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 (stale).
Under these conditions, some host applications 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. Doing so can invalidate snapshot volumes.
NOTE: By default, the growth warning and growth limit are set to <none>, which
effectively disables these safety features.