Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

Figure 1-12
Example of concatenation
Plex with concatenated subdisks
Data blocks
Subdisks
VM disk
Physical disk
disk01-01
Data in
disk01-01
Data in
disk01-03
disk01-03
disk01-02disk01-01 disk01-03
devname
disk01-01 disk01-03
disk01
n n+1 n+2 n+3
n n+1 n+2 n+3
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 on the same
physical disk.
The remaining free space in the subdisk, disk01-02, on VM disk, disk01, can be
put to other uses.
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.
39Understanding Veritas Volume Manager
Volume layouts in VxVM