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

ionice -c3 find /
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.

6
By: mkc
2009-02-19 17:23:12

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    slow2() { ionice -c3 renice -n 20 $(pstree `pidof $1` -p -a -u -A|gawk 'BEGIN{FS=","}{print $2}'|cut -f1 -d " ") ; }
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    cd /proc&&ps a -opid=|xargs -I+ sh -c '[[ $PPID -ne + ]]&&echo -e "\n[+]"&&tr -s "\000" " "<+/cmdline&&echo&&tr -s "\000\033" "\nE"<+/environ|sort'
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What Others Think

The -c3 refers to the idle priority class, which according to the manpage is only permitted for root. Therefore the line should read: # ionice -c3 find /
markrian · 450 weeks and 6 days ago
Erm, having now tried it, it seems the manpage is talking rubbish. Any user can change their own processes to idle priority!
markrian · 450 weeks and 6 days ago
Yeah, I'm a little unclear on this. It seems like I was able to do it as a regular user at some point, but now maybe root is required. I think non-root access to this is considered to be a security hole (for somewhat obscure reasons).
mkc · 450 weeks and 6 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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