VERITAS Volume Manager 4.1 Administrator's Guide

Performance Monitoring and Tuning
Performance Monitoring
Chapter 12 399
In the configuration example shown in the figure “Use of Mirroring and
Striping for Improved Performance” the read policy of the
mirrored-stripe volume labeled Hot Vol is set to prefer for the striped
plex PL1. This policy distributes the load when reading across the
otherwise lightly-used disks in PL1, as opposed to the single disk in plex
PL2.(HotVol is an example of a mirrored-stripe volume in which one data
plex is striped and the other data plex is concatenated.)
Figure 12-2 Use of Mirroring and Striping for Improved Performance
NOTE To improve performance for read-intensive workloads, you can attach up
to 32 data plexes to the same volume. However, this would usually be an
ineffective use of disk space for the gain in read performance.
Performance Monitoring
As a system administrator, you have two sets of priorities for setting
priorities for performance. One set is physical, concerned with hardware
such as disks and controllers. The other set is logical, concerned with
managing software and its operation.
Disk 1 Disk 2 Disk 3 Disk 4
HotVol
PL1 SD1
HotVol
PL1 SD2
HotVol
PL1 SD3
Lightly
Used
Area
Lightly
Used
Area
Lightly
Used
Area
Lightly
Used
Area
HotVol
PL2 SD1