Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

# 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 305.
The maximum size of a VxVM volume that you can create is 256TB.
Disk group alignment constraints on volumes
Certain constraints apply to the length of volumes and to the numeric values of
size attributes that apply to volumes. If a volume is created in a disk group that
is compatible with the Cross-platform Data Sharing (CDS) feature, the volume’s
length and the values of volume attributes that define the sizes of objects such
as logs or stripe units, must be an integer multiple of the alignment value of 8
blocks (8 kilobytes). If the disk group is not compatible with the CDS feature, the
volume’s length and attribute size values must be multiples of 1 block (1kilobyte).
To discover the value in blocks of the alignment that is set on a disk group, use
this command:
# vxprint -g diskgroup -G -F %align
By default, vxassist automatically rounds up the volume size and attribute size
values to a multiple of the alignment value. (This is equivalent to specifying the
attribute dgalign_checking=round as an additional argument to the vxassist
command.)
If you specify the attribute dgalign_checking=strict to vxassist, the command
fails with an error if you specify a volume length or attribute size value that is
not a multiple of the alignment value for the disk group.
Creating a volume on any disk
By default, the vxassist make command creates a concatenated volume that uses
one or 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.
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 space spread
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.
Creating volumes
Disk group alignment constraints on volumes
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