Re: [gentoo-user] Web Server Memory Issues

[Kaddeh]

Jarry,

Thanks for the monitoring advice, I am checking out monit right now.

In terms of what is the root cause of the issue, I have narrowed it down to
either write caching of a SQL cache issue.

First, addressing the SQL issue and why I think that that could be one of
the causes.  The entire site, for the most part is all in one giant DB
(~9GB) a significant part of that is a 3gb table full of raw image data
(yes, I know that this is a REALLY bad idea to do, but I didn't design the
site, I just did a migration to off-site) that being said, there could be a
problem with that.

The write caching hteroy just comes up because I can clear the cached memory
down to 14mb cached using 'sync && echo 3 > /proc/sys/vm/dump_cache'

Cheers

Kad

On Wed, Jan 12, 2011 at 1:37 PM, Jarry <mr.jarry@×××××.com> wrote:

> On 12. 1. 2011 19:59, Kaddeh wrote:
>
>  P4 @ 3.0Ghz
>> 2GB PC2 4200
>> 2x 250GB drives in RAID1
>> The system configurations are default for the most part with the server
>> running MySQL and Apache.
>> The problem that I am running into at this point, however is that the
>> machine seems to run out of memory and will segfault either apache or
>> mysql when does so, when apache segfaults, it is a recoverable error,
>> when mysql does it, mysql can't recover short of restarting it.
>> At this point, I have found a soft fix by running a cron job every 6
>> hours or so to clear the cached memory, which seems to be the problem,
>> however, I would like to find a more permanent fix to this issue.
>>
>
> First of all, find what is causing that excessive memory usage.
> I think 2GB should be enough for moderate web with apache+mysql.
>
> Second, use some monitoring software. Personally I'm using
> "monit" and I am very satisfied with it. It can monitor processes
> (if it is running, answering requests, etc), resources (disk,
> memory, swap, cpu, i/o), files (content, permissions, checksums),
> remote hosts (with some basic protocol checks i.e. http, ssh,
> smtp, ftp, mysql, ntp, dns...), it can inform you about problems
> (mail, log) and you can define rules what to do in case of anomalies
> (i.e. if mysql is using to much memory, it will be restarted).
>
> It can start/restart processes if they die (happened to me once
> with sshd on server which was ~50 miles away from me). You can
> put monit in inittab, so in case monit itself dies it is restarted
> automatically. Etc, etc.
>
> Jarry
>
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