Limiter l'utilisation des I/O par une application

1 Introduction

Want to know why your load average is so high? Run this command to see what processes are on the run queue. Runnable processes have a status of "R", and commands waiting on I/O have a status of "D".

Once found, you may need to reduce its I/O requests, so we'll use ionice.

2 Get I/O apps

To get the biggests apps I/O :

ps -eo stat,pid,user,command

On some older versions of Linux may require -emo instead of -eo.

And on Solaris :

ps -aefL -o s -o user -o comm

3 Ionice

ionice limits process I/O, to keep it from swamping the system (Linux)

This command is somewhat similar to 'nice', but constrains I/O usage rather than CPU usage. In particular, the '-c3' flag tells the OS to only allow the process to do I/O when nothing else is pending. This dramatically increases the responsiveness of the rest of the system if the process is doing heavy I/O.

There's also a '-p' flag, to set the priority of an already-running process.

ionice

ionice -c3 find /