VERITAS Storage Foundation 4.1 Intelligent Storage Provisioning Administrator's Guide

The Benefits of ISP
14 VERITAS Storage Foundation ISP Administrator’s Guide
Traditional Model for Creating and Administering Volumes in VERITAS Volume Manager
When intelligent disk arrays are used, many sophisticated features, such as RAID capabilities,
snapshot facilities, and remote replication, are provided by logical unit storage devices, LUNs, that
are exported by the disk array. Such devices may or may not have ways of making their attributes
known to VxVM. In any case, you may be presented with hundreds or thousands of LUNs
connected over a SAN.
Allocating storage to volumes when faced with a potentially large number of devices with widely
varying and possibly hidden properties is a daunting task to perform manually. ISP aids you in
managing large sets of storage by providing an allocation engine that chooses which storage to use
based on the capabilities that you specify for the volumes to be created.
“How ISP Enhances Volume Management” on page 15 illustrates how ISP improves on the
traditional model for creating volumes. The main differences are that the set of information about
the available storage is potentially unlimited, and the set of rules that the allocation engine uses to
choose storage is defined externally to commands such as vxvoladm.
Storage within a Disk Group
Volumes are built from the
available storage according
to hard-coded rules, and as
explicitly specified by you.
Knowledge of storage attributes
in VxVM is limited to
automatically discovered
information such as enclosure
membership, and path and
controller connectivity. Beyond
this, you must state explicitly
which storage to use.
User specifications
Attributes
The vxassist command uses
hard-coded rules to create
and administer volumes. You
can override these rules by
stating explicitly which
storage is to be used.
vxassist
for volume layout
Vo l u m e s