240Creating volumes

Using vxassist

■Operations result in a set of configuration changes that either succeed or fail as a group, rather than individually. System crashes or other interruptions do not leave intermediate states that you have to clean up. If vxassist finds an error or an exceptional condition, it exits after leaving the system in the same state as it was prior to the attempted operation.

The vxassist utility helps you perform the following tasks:■Creating volumes.■Creating mirrors for existing volumes.■Growing or shrinking existing volumes.■Backing up volumes online.■Reconfiguring a volume’s layout online.

vxassist obtains most of the information it needs from sources other than your input. vxassist obtains information about the existing objects 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 takes this form:#vxassist [options] keyword volume [attributes...]

where keyword selects the task to perform. The first argument after a vxassist keyword, volume, is a volume name, which is followed by a set of desired volume attributes. For example, the keyword make allows you to create a new volume:

#vxassist [options] make volume length [attributes]

The length of the volume can be specified in sectors, kilobytes, megabytes, or gigabytes using a suffix character of s, k, m, or g. If no suffix is specified, the size is assumed to be in sectors. See the vxintro(1M) manual page for more information on specifying units.

Additional attributes can be specified as appropriate, depending on the characteristics that you wish the volume to have. Examples are stripe unit width, number of columns in a RAID-5 or stripe volume, number of mirrors, number of logs, and log type.

Note: By default, the vxassist command creates volumes in a default disk group according to the rules given in “Rules for determining the default disk group” on page 168. To use a different disk group, specify the -gdiskgroup option to

vxassist.

For details of available vxassist keywords and attributes, refer to the vxassist(1M) manual page.