VERITAS Volume Manager 3.1 Reference Guide

16 Chapter1
Volume Manager Commands
vxassist - creating and changing volumes
• vxassist tasks result in a set of configuration changes that either
succeed or fail as a group, rather than individually. Most vxassist
tasks work so that system crashes or other interruptions do not leave
intermediate states to be cleaned up. If vxassist finds an error or an
exceptional condition, it exits without leaving partially-changed
configurations. The system is left in the same state as it was prior to
the attempted vxassist task.
How vxassist Works
The vxassist command allows you to create and modify volumes. You
specify the basic volume creation or modification requirements and
vxassist performs the necessary tasks.
vxassist obtains most of the information it needs from sources other
than your input. vxassist obtains information about the existingobjects
and their layouts from the objects themselves.
For tasks requiring new disk space, vxassist seeks out available disk
space and allocates it in the configuration that conforms to the layout
specifications and that offers the best use of free space.
The vxassist command typically takes this form:
vxassist keyword volume_name [attributes...]
where keyword selects the task to perform. The first argument after a
vxassist keyword is a volume name, which is followed by a set of
attributes. For details on available vxassist keywords and attributes,
refer to the vxassist(1M) manual page.
vxassist creates and manipulates volumes based on a set of established
defaults, but also allows you to supply preferences for each task.
vxassist Defaults
vxassist uses a set of tunable parameters that can be specified in the
defaults files or at the command line. The tunable parameters default to
reasonable values if they are not listed on the command line. Tunables
listed on the command line override those specified elsewhere. Here are
the tunable parameters:
• Internal defaults—The built-in defaults areused when the value for a
particular tunable is not specified elsewhere (on the command line or
in a defaults file).