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

34 Understanding Veritas Volume Manager
Volume layouts in VxVM
Figure 1-12 Example of concatenation
You can use concatenation with multiple subdisks when there is insufficient contiguous
space for the plex on any one disk. This form of concatenation can be used for load
balancing between disks, and for head movement optimization on a particular disk.
Figure 1-13 shows data spread over two subdisks in a spanned plex. The blocks n, n+1,
n+2 and n+3 (numbered relative to the start of the plex) are contiguous on the plex, but
actually come from two distinct subdisks from two distinct physical disks.
The remaining free space in the subdisk disk02-02 on VM disk disk02 can be put to
other uses.
disk01
VM disk
Physical disk
Plex with
Data blocksnn+1n+2n+3
devname
disk01-01 disk01-03
disk01-01 disk01-03
Subdisks
nn+1 n+2 n+3
disk01-02
Data in
disk01-01
Data in
disk01-03
disk01-03disk01-01
concatenated subdisks