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

40 Understanding ISP
About ISP concepts
About capabilities
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 “Capability” on page 185 for details of the capabilities that are provided.
About performance capabilities
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.