Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

246 Creating volumes

Mirroring across targets, controllers or enclosures

To create a volume whose mirrored data plexes lie on different controllers (also known as

disk duplexing) or in different enclosures, use the

vxassist command as described in this

section.

In the following command, 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=target [attributes]

The attribute mirror=ctlr specifies that disks in one mirror should not be on the same

controller as disks in other mirrors within the same volume:

# vxassist [-b] [-g diskgroup] make volume length \

layout=layout mirror=ctlr [attributes]

Note: Both paths of an active/passive array are not considered to be on different

controllers when mirroring across controllers.

The following command creates a mirrored volume with two data plexes in the disk group,

mydg:

# vxassist -b -g mydg make volspec 10g layout=mirror nmirror=2 \

mirror=ctlr ctlr:c2 ctlr:c3

The disks in one data plex are all attached to controller c2, and the disks in the other data

plex are all attached to controller c3. This arrangement ensures continued availability of

the volume should either controller fail.

The attribute

mirror=enclr specifies that disks in one mirror should not be in the same

enclosure as disks in other mirrors within the same volume.

The following command creates a mirrored volume with two data plexes:

# vxassist -b make -g mydg volspec 10g layout=mirror nmirror=2 \

mirror=enclr enclr:enc1 enclr:enc2

The disks in one data plex are all taken from enclosure enc1, and the disks in the other

data plex are all taken from enclosure enc2. This arrangement ensures continued

availability of the volume should either enclosure become unavailable.

See “Specifying ordered allocation of storage to volumes” on page 236 for a description of

other ways in which you can control how volumes are laid out on the specified storage.