Ionice
General Information
ionice - set or get process I/O scheduling class and priority
ionice can be used in combination with rm to remove very large files and not impact other, more high priority processes.
Scheduling Classes/Priority Levels
Available scheduling classes are:
- 0 → none (equivalent to the default of 2)
- 1 → real time - first, priority access to the disk, only available to root user
- 2 → best effort (default if not specified)
- 3 → idle - use cpu only when no other process has asked for cpu time
Priority Levels:
- 0-7
- 0 → Highest priority
- 7 → Lowest priority
Get Process I/O Info
Example of Getting the i/o scheduling class and priority of a process with PID 1637
> $ ionice -p 1637 none: prio 0
Set Class/Priority
Remove a large file, using only idle cpu time
ionice -c 3 rm /var/log/mylargelog
Remove a large file, use best effort scheduling, with a low priority
ionice -n 7 rm /var/log/mylargelog