HP Veritas Volume Manager 5.0 -UX 11i v3 manual Example of concatenation Data Disk01-01

36Understanding Veritas Volume Manager

Volume layouts in VxVM

Figure 1-12 Example of concatenation

Data in	Data in
disk01-01	disk01-03

n n+1 n+2 n+3

disk01-01 disk01-03

Data blocks

Plex with

concatenated subdisks

disk01-01 disk01-03

Subdisks

disk01-01 disk01-02 disk01-03	VM disk
disk01

devname

n n+1 n+2

n+3

Physical disk

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 1-13shows 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 disk02-02on VM disk disk02 can be put to other uses.