VERITAS Storage Foundation 4.1 Intelligent Storage Provisioning Administrator's Guide

ISP Concepts
8 VERITAS Storage Foundation ISP Administrator’s Guide
Capability
A capability is a feature that is provided by a volume. For example, a volume may exhibit
capabilities such as performance and reliability to various degrees. Each type of capability is
defined as a set of rules.
The following table shows some simple examples of capabilities that might be supported by a
storage pool:
Capabilities have variable parameters that you can specify, such as the number of mirrors or
columns. You can adjust the values of these parameters to tune the characteristics of a volume. If
you do not specify parameter values, default values are used.
See “Capabilities” on page 165 for details of the capabilities that are provided.
How capabilities are used to specify performance and reliability characteristics is described in the
following sections.
Performance
Performance specifies the capabilities of a volume based on factors such as number of columns in
striped volumes, stripe unit size, preferred characteristics of storage such as using prefabricated
disks that are configured in hardware.
Capability Adjustable Parameters Description
DataMirroring nmirs — number of mirrors (plexes) Provides reliability by using
mirrored plexes.
Raid5Capability ncols — minimum number of columns
nmaxcols — maximum number of columns
Provides reliability by using
RAID-5 parity.
Raid5LogMirroring nlogs — number of log copies Provides reliability for
RAID-5 logs by mirroring.
Striping ncols — minimum number of columns
nmaxcols — maximum number of columns
Provides performance by
striping across columns.