Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

For example, you can create allocation rules so that a set of servers can standardize
their storage tiering. Suppose you had the following requirements:
Enclosure mirroring between a specific set of array typesTier 1
Non-mirrored striping between a specific set of array typesTier 2
Select solid-state drive (SSD) storageTier 0
You can create rules for each volume allocation requirement and name the rules
tier1, tier2, and tier0.
You can also define rules so that each time you create a volume for a particular
purpose, it's created with the same attributes. For example, to create the volume
for a production database, you can create a rule called productiondb. To create
standardized volumes for home directories, you can create a rule called homedir.
To standardize your high performance index volumes, you can create a rule called
dbindex.
Understanding persistent attributes
The vxassist command also lets you record certain volume allocation attributes
for a volume. These attributes are called persistent attributes. You can record the
attributes which would be useful in later allocation operations on the volume.
Useful attributes include volume grow and enclosure mirroring. You can also
restrict allocation to storage that has a particular property (such as the enclosure
type, disk tag, or media type). On the other hand, volume length is not useful, and
generally neither is a specific list of disks.
The persistent attributes can be retrieved and applied to the allocation requests
(with possible modifications) for the following operations:
■ volume grow or shrink
■ move
■ relayout
■ mirror
■ addlog
Persistent attributes let you record carefully described allocation attributes at
the time of volume creation and retain them for future allocation operations on
the volume. Also, you can modify, enhance, or even discard the persistent
attributes. For example, you can add and retain a separation rule for a volume
that is originally not mirrored. Alternatively, you can temporarily suspend a
329Creating volumes
Using rules and persistent attributes to make volume allocation more efficient