Veritas Storage Foundation Intelligent Storage Provisioning 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

17Understanding ISP
The benefits of ISP
Figure 1-1 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.
Figure 1-2 illustrates how ISP improves on the traditional model for creating
volumes. The main differences are that the set of information about the
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
Volumes