VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Chapter 7, Creating Volumes
Discovering the Maximum Size of a Volume
165
Discovering the Maximum Size of a Volume
To findout how largea volume you cancreatewithin a diskgroup,use the followingform
of the vxassist command:
# vxassist [-g diskgroup] maxsize layout=layout [attributes]
For example, to discover the maximum size RAID-5 volume with 5 columns and 2 logs
that you can create within the disk group dgrp, enter the following command:
# vxassist -g dgrp maxsize layout=raid5 nlog=2
You can use storage attributes if you want to restrict the disks that vxassist uses when
creating volumes. See “Creating a Volume on Specific Disks” on page 166 for more
information.
Creating a Volume on Any Disk
By default, the vxassist make command creates a concatenatedvolume thatuses oneor
more sections of disk space. On a fragmented disk, this allows you to put together a
volume larger than any individual section of free disk space available.
Note To change the default layout, edit the definition of the layout attribute defined in
the /etc/default/vxassist file.
If there is not enough space on a single disk, vxassist creates a spanned volume. A
spanned volume is a concatenated volume with sections of disk spacespread across more
than one disk. A spanned volume can be larger than any disk on a system, since it takes
space from more than one disk.
To create a concatenated, default volume, use the following form of the vxassist
command:
# vxassist [-b] [-g diskgroup] make volume length
Note Specify the -b option if you want to make the volume immediately available for
use. See “Initializing and Starting a Volume” on page 181 for details.
For example, to create the concatenated volume voldefault with a length of 10
gigabytes in the rootdg disk group:
# vxassist -b make voldefault 10g