Re: [gentoo-user] mysqld invoked oom-killer

[Grant]

>> I ran into an out of memory problem.  The first mention of it in the
>> kernel log is "mysqld invoked oom-killer".  I haven't run into this
>> before.  I do have a swap partition but I don't activate it based on
>> something I read previously that I later found out was wrong so I
>> suppose I should activate it.  Is fstab the way to do that?  I have a
>> commented line in there for swap.
...
> If you're running any other servers that utilize MySQL like Apache or
> something, check its access logs to see if you had an abnormal number
> of connections. Bruteforce hacking or some kind of flooding/DOS attack
> might cause it to use more memory than it ordinarily would.

I don't know why I didn't check the apache2 error log before, but I
got the following entry 2 seconds before the server became
unresponsive:

[error] server reached MaxClients setting, consider raising the
MaxClients setting

I use the default 256 for MaxClients.  This confirms the server was
brought down by too many child processes consuming too much memory.
Looking back at the access_log, it's clear this condition was caused
by the single IP which requested one of my pages about 300 times over
the course of 1 minute.  This caused my entire server to lock up for
hours until I rebooted it.

I hesitate to reduce MaxClients from 256.  I think my server should be
able to handle it since it's the default.  So I need to prevent my
apache2 child processes from consuming so much memory?  apache2 was
restarted about an hour before the lockup so it had a pretty fresh
start.  I do use mod_perl which is a memory hog from what I
understand.  Do I just need more RAM?

- Grant