---
title: nice and ionice
keywords: [linux, unix, nice, ionice, tip, howto, job scheduling]
---

You can reduce the impact of a job by combining these two commands:

1. `nice` modify the cpu scheduling of a command. Nicenesses range from
   -20 (most favorable scheduling) to 19 (least favorable)

2. `ionice` modify the io scheduling class and priority of a command

options:

* `-c` The scheduling class
    * 1 for real time
    * 2 for best-effort
    * 3 for idle
* `-n` The scheduling class data. This defines the class data, if the
  class accepts an argument. For real time and best-effort, 0-7 is valid
  data

* `-p` Pass in a process pid to change an already running process. If
  this argument is not given, ionice will run the listed program with the
  given parameters

I have used the below command on my own servers and it works well:

``` bash
/usr/bin/nice -n 19 /usr/bin/ionice -c2 -n7 /usr/local/bin/backup.sh
```

These articles may also be of help:

* [reduce load of backup scripts](http://www.faqforge.com/linux/reduce-load-of-backup-scripts-with-nice-and-ionice/)
* [set io scheduling](http://www.cyberciti.biz/tips/linux-set-io-scheduling-class-priority.html)