OOM on Linode1024

From what you posted, your server looks OK for now.

What are you running on the Linode, e.g. WordPress, Drupal, phpBB, etc? Does any of that involve image processing, like generating thumbnails from large photos?

Is there anything else running on the server, e.g. dovecot?

Please post your httpd.conf and my.cnf. Those are the usual suspects.

This is my my.cnf

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Default to using old password format for compatibility with mysql 3.x
# clients (those using the mysqlclient10 compatibility package).
#old_passwords=1

# Disabling symbolic-links is recommended to prevent assorted security risks;
# to do so, uncomment this line:
# symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

[mysqld]
# someother settings
socket=/var/lib/mysql/mysql.sock

#added these lines for foreign characters
[client]
socket=/var/lib/mysql/mysql.sock
default-character-set=utf8
[mysqld]
default-character-set = utf8
skip-character-set-client-handshake
character-set-server = utf8
collation-server = utf8_general_ci

init-connect = "SET collation_connection = utf8_general_ci"
init-connect = "SET NAMES utf8"

This is a part of my httpd.conf

# prefork MPM
# StartServers: number of server processes to start
# MinSpareServers: minimum number of server processes which are kept spare
# MaxSpareServers: maximum number of server processes which are kept spare
# ServerLimit: maximum value for MaxClients for the lifetime of the server
# MaxClients: maximum number of server processes allowed to start
# MaxRequestsPerChild: maximum number of requests a server process serves
 <ifmodule prefork.c="">StartServers       8
MinSpareServers    5
MaxSpareServers   20
ServerLimit      256
MaxClients       256
MaxRequestsPerChild  4000</ifmodule> 

# worker MPM
# StartServers: initial number of server processes to start
# MaxClients: maximum number of simultaneous client connections
# MinSpareThreads: minimum number of worker threads which are kept spare
# MaxSpareThreads: maximum number of worker threads which are kept spare
# ThreadsPerChild: constant number of worker threads in each server process
# MaxRequestsPerChild: maximum number of requests a server process serves
 <ifmodule worker.c="">StartServers         2
MaxClients         150
MinSpareThreads     25
MaxSpareThreads     75
ThreadsPerChild     25
MaxRequestsPerChild  0</ifmodule> 

I am running Wordpress and some custom made sites with Perl. I don't use any image processing at all.

I do a lot of MySQL database operations but I'm not sure if that's the cause.

Any thoughts on my configurations?

You seem to have left out a huge chunk of my.cnf. Where's the part with key_buffer and all those memory usage settings?

But never mind, here's your most likely culprit.

 <ifmodule prefork.c="">StartServers       8
MinSpareServers    5
MaxSpareServers   20
ServerLimit      256
MaxClients       256</ifmodule> 

That should be changed to something like:

 <ifmodule prefork.c="">StartServers       4
MinSpareServers    4
MaxSpareServers    8
ServerLimit       24
MaxClients        24</ifmodule> 

Restart Apache, and you'll probably not see another OOM for a long time.

Thank you so much. I applied these changes and hope the OOM issue is completely gone.

My suggestion is start monitoring the instance so you know it's not responding. Something like nagios will work.