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

Mirroring plus striping (striped-mirror, RAID-1+0 or RAID-10)
VxVM supports the combination of striping above mirroring. This combined layout
is called a striped-mirror layout. Putting mirroring below striping mirrors each
column of the stripe. If there are multiple subdisks per column, each subdisk can
be mirrored individually instead of each column.
A striped-mirror volume is an example of a layered volume.
See “Layered volumes” on page 49.
As for a mirrored-stripe volume, a striped-mirror volume offers the dual benefits
of striping to spread data across multiple disks, while mirroring provides
redundancy of data. In addition, it enhances redundancy, and reduces recovery
time after disk failure.
Figure 1-18 shows an example where a striped-mirror volume is created by using
each of three existing 2-disk mirrored volumes to form a separate column within
a striped plex.
Figure 1-18
Striped-mirror volume laid out on six disks
Striped plex
Mirror
column 0 column 1
column 0 column 1
Striped-mirror
volume
Underlying mirrored volumes
column 2
column 2
See “Creating a striped-mirror volume” on page 319.
Figure 1-19 shows that the failure of a disk in a mirrored-stripe layout detaches
an entire data plex, thereby losing redundancy on the entire volume.
43Understanding Veritas Volume Manager
Volume layouts in VxVM