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

Chapter 7, Creating Volumes
Mirroring across Targets, Controllers or Enclosures
175
Creating a Striped-Mirror Volume
A striped-mirror volume is an example of a layered volume which stripes several
underlying mirror volumes.
Note A striped-mirror volume requires space to be available on at least as many disks in
the disk group as the number of columns multiplied by the number of stripes in the
volume.
To create a striped-mirror volume, use the following command:
# vxassist [-b] [-g diskgroup] make volume length \
layout=stripe-mirror [nmirror=number_mirrors] \
[ncol=number_columns] [stripewidth=size]
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.
By default, VxVM attempts to create the underlying volumes by mirroring subdisks
rather than columns if the size of each column is greater than the value for the attribute
stripe-mirror-col-split-trigger-pt that is defined in the vxassist defaults
file.
If there are multiple subdisks per column, you can choose to mirror each subdisk
individually instead of each column. To mirror at the subdisk level, specify the layout as
stripe-mirror-sd rather thanstripe-mirror. To mirror at thecolumn level, specify
the layout as stripe-mirror-col rather than stripe-mirror.
Mirroring across Targets, Controllers or Enclosures
To create a volume whose mirrored data plexes lie on different controllers, you can use
either of the commands described in this section.
# vxassist [-b] [-g diskgroup] make volume length layout=layout \
mirror=target [attributes]
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.
The attribute mirror=target specifies that volumes should be mirrored between
identical target IDs on different controllers.
# vxassist [-b] [-g diskgroup] make volume length layout=layout \
mirror=ctlr [attributes]