hm - my servers generally have no swap or better said
only a 500 MB swap-file, they are all virtual machines
in a ESXi cluster
you really do not want a VM swapping
this leads in unusaeable performance
in my case the problem was another process eating up all memory
by user-mistake and my hint is to make sure in this case that
this process get killed and never mysqld
but i never ever had to reboot any linux guest to get it back to life
Am 13.04.2012 16:27, schrieb Johnny Withers:
> I had this same problem with the OOM for a while. Very frustrating to have to reboot
> a server to bring it back to life.
>
> I found out the OOM only ran when the swap file was about 99% full. The servers I had
> this problem on had 16GB and
> 24GB of ram, but only 2GB of swap. I increased the swap on the 24GB servers to 48GB
> and on the 16GB servers to
> 32GB. The swap never fills to over 60% now and I haven't' had any OOM problems since
> and the systems run great.
>
> I've also set vm.swappiness=0 in /etc/sysctl.conf
>
> -JW
>
> On Fri, Apr 13, 2012 at 7:17 AM, Reindl Harald <h.reindl@stripped
> <mailto:h.reindl@stripped>> wrote:
>
> the following may be useful for most server systems
>
> OOM-killer acts if some process reclaims more and more
> memory and the kernel randomly kills unimportant tasks
> using hughe memory
>
> in case of a running mysqld the classification "unimportant"
> is nearly all time wrong and can cause hughe damage and work
> in other words: you really never want killed a database server
> randomly instead "dbmail-imapd" which can be restarted via
> systemd without pain and may be the root-cause of OOM
> _________________________________________
>
> with one single command you can protect processes from get killed
> i started to run this every 15 minutes to make sure it is also
> active after restarts
>
> i am considering include this in "mysqld.service" as
> "ExecStartPost=-/usr/local/bin/mysql-no-oom.sh" in our
> internal mysqld-packages and include also the script
> _________________________________________
>
> [root@mail:~]$ cat /etc/crontab | grep oom
> 0,15,30,45 * * * * root bash /usr/local/bin/mysql-no-oom.sh
>
> [root@mail:~]$ cat /usr/local/bin/mysql-no-oom.sh
> #!/bin/bash
> pgrep -f "/usr/libexec/mysqld" | while read PID; do echo -1000 >
> /proc/$PID/oom_score_adj; done
>
>
>
>
> --
> -----------------------------
> Johnny Withers
> 601.209.4985
> johnny@stripped <mailto:johnny@stripped>
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