chu_bun

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I had a server that ran fine for years. But after upgrading to the latest version of CentOS and httpd, my server keeps on locking up when there are too many connections (under a nikto security scan for example).

I found lines like this in the message log
kernel: [<c0459c79>] out_of_memory+0x72/0x1a5 httpd invoked oom-killer: gfp_mask=0x201d2, order=0, oomkilladj=0
kernel: [<c0459c79>] out_of_memory+0x72/0x1a5
...
kernel: Total swap = 2096440kB
kernel: Free swap: 0kB

"top" would show about a bunch of httpd processes taking up 5, 10% of MEM. The only non-default setups are
post_max_size = 200M
upload_max_filesize = 200M
max_execution_time = 72000
max_input_time = 72000
in php.ini

I tried very small value for ServerLimit and MaxClients (10, 15) and these seems to prevent the server from hanging, but still the MEM% went to dangerously value (> 5%).

My provider blames it on a mem leak in http/mod_ssl, but I'm not so sure. Any suggestions? Thank you.

kirukan

access.log file size also effect the usage of total httpd memory usage. so just verify the access.log size

chu_bun

On our test server, log file size is only 5+ MBytes. And it runs into the same problems as the production servers (300+ MBytes).

Here is an errata on the problem:
https://rhn.redhat.com/errata/RHSA-2009-1075.html

But the update does not fix the problem!