VERITAS Storage Foundation 4.1 Intelligent Storage Provisioning Administrator's Guide

Chapter 1, Understanding ISP

The Benefits of ISP

When creating a volume in VERITAS Volume Manager in previous releases, you could specify the

disk storage on which to lay out its various parts, subdisks, plexes, and so on. In specifying the

storage to be used, you had to take into account the tolerance of a volume to failure of any

component of the storage infrastructure, and how the specified layout affected I/O performance and

reliability of service. For small installations with a few tens of disks in relatively low-specification

arrays, you could either specify the storage layout manually to commands such as vxassist, or

rely on vxassist to choose appropriate storage based on general layout specification, such as

“mirror across controllers” and “mirror across enclosures,” and using the set of heuristic rules that

are hard-coded within vxassist.

The traditional model for allocating storage to volumes is shown in “Traditional Model for Creating

and Administering Volumes in VERITAS Volume Manager” on page 14. This illustrates that,

although some storage attributes are known to VxVM, you must do most of the work in deciding

how to lay out the storage if you are to create a volume with the desired performance, reliability

and fault tolerance.