
460 DS8800 Performance Monitoring and Tuning
Using ionice to assign I/O priority
A feature of the CFQ I/O elevator is the option to assign priorities on a process level. By using
the ionice utility, you can restrict the disk subsystem utilization of a specific process:
Idle: A process with the assigned I/O priority
idle is granted access to the disk subsystems
if no other processes with a priority of
best-effort or higher request access to the data. This
setting is useful for tasks that run when the system has free resources, such as the
updatedb task.
Best-effort: As a default, all processes, which do not request a specific I/O priority, are ...