Every once in a while I was getting these OSSEC notifications (see below) and just played them off. Well the other day while downloading a backup to my PC I was getting them every few minutes. I rebooted and tried again....same thing....they would come in every few minutes.

I am running: CentOS 5.5 Profile (Latest 3.5 (3.5.2-linode45)) ... I did some searching and saw some people had a similar issue a while back but supposedly upgrading the Kernal fixed it :/

Any ideas?

OSSEC HIDS Notification.
2012 Sep 30 09:35:11

Received From: cathode->/var/log/messages
Rule: 1002 fired (level 2) -> "Unknown problem somewhere in the system."
Portion of the log(s):

Sep 30 09:35:11 cathode kernel: swapper/0: page allocation failure: order:4, mode:0x20



 --END OF NOTIFICATION

There's a long thread on it here viewtopic.php?f=20&t=7805&hilit=page+allocation the general solution is to increase vm.min_free_kbytes to a minimum of 4096 (I had to go as far as 8192 on one server)

_________________
Paid support
How to ask for help
1. Give details of your problem
2. Post any errors
3. Post relevant logs.
4. Don't hide details i.e. your domain, it just makes things harder
5. Be polite or you'll be eaten by a grue

From what I understood, I need to make that change in /etc/sysctl.conf but that does not even exist in there.... nothing close to it even. Do I just need to add it all together, or am I still missing something?

Add it in at the end of the file and then run "sysctl -p" to apply it.

Pages to help your familiarity with sysctl and it's features.
http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-proc-sysctl.html
http://www.centos.org/docs/2/rhl-rg-en-7.2/s1-proc-sysctl.html

Hope this helps.