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

Figure 1-16
Example of a striped plex with concatenated subdisks per column
Subdisks
Striped plex
Stripe units
VM disks
Column 0
Physical disks
devname1
su1 su2 su3 su4
su1 su4
devname2
su2 su5
devname3
su3 su6
su5 su6
disk01-01
Column 1
disk02 disk03disk01
disk02-01
disk02-02
Column 2
disk03-01
disk03-02
disk03-03
disk01-01
disk02-01
disk02-02
disk03-01
disk03-02
disk03-03
disk01-01
disk02-01
disk02-02
disk03-01
disk03-02
disk03-03
Each column contains a different number of subdisks. There is one column per
physical disk. Striped plexes can be created by using a single subdisk from each
of the VM disks being striped across. It is also possible to allocate space from
different regions of the same disk or from another disk (for example, if the size
of the plex is increased). Columns can also contain subdisks from different VM
disks.
See “Creating a striped volume” on page 317.
Mirroring (RAID-1)
Mirroring uses multiple mirrors (plexes) to duplicate the information contained
in a volume. In the event of a physical disk failure, the plex on the failed disk
becomes unavailable, but the system continues to operate using the unaffected
mirrors. Similarly, mirroring two LUNs from two separate controllers lets the
system operate if there is a controller failure.
41Understanding Veritas Volume Manager
Volume layouts in VxVM