topic Re: memoryleak? oomkiller kills processes in Operating System - Linux

memoryleak? oomkiller kills processes

Donald Kok — Wed, 16 Mar 2005 08:20:42 GMT

Hi,

Fedora core 3 runlevel 3 used as a webserver
Since a while this system is loosing memory . When the memory is empty oom-killer kills processes f.i. httpd mysqld. So the systems becomes unusable.
I have no process withs consumes the load of memory

After a reboot the same happens again.

How can I find the "thing" that takes the memory?

Thanks in Advance
Donald

Re: memoryleak? oomkiller kills processes

Steven E. Protter — Wed, 16 Mar 2005 08:47:05 GMT

I you have time, you need to figure out where the leak is.

It could be the httpd server itself. It could be mysql. It could be a DOS type attack on the httpd server or other application.

Shut down and leave shut down suspected applications one at a time until the system is stable. Then you know which application to focus on.

If its a httpd attack, check the access_log file for entires that don't belong. If the machine is exposed to the Internet and there are a lot of gets or posts to websites you don't host, you have a DOS problem and I can provide specific help on stopping it.

SEP

Re: memoryleak? oomkiller kills processes

Vitaly Karasik_1 — Thu, 17 Mar 2005 03:20:49 GMT

Donald, what do you see in the top of "top"
output [sort by memory usage by press "M"]?

Re: memoryleak? oomkiller kills processes

Donald Kok — Fri, 18 Mar 2005 05:31:12 GMT

The biggest poces is httpd with 10M.
There is 4M free at the moment, while swap is almost unused.
Here follows the output of vmstat and top
vmstat -s -S M -a
503 M total memory
495 M used memory
170 M active memory
230 M inactive memory
7 M free memory
211 M buffer memory
161 M swap cache
1960 M total swap
25 M used swap
1935 M free swap

top (ordered by memory:)
top - 11:23:36 up 2 days, 1:57, 2 users, load average: 0.01, 0.03, 0.00
Tasks: 67 total, 1 running, 66 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.3% us, 0.0% sy, 0.0% ni, 99.7% id, 0.0% wa, 0.0% hi, 0.0% si
Mem: 515116k total, 501692k used, 13424k free, 216304k buffers
Swap: 2008040k total, 25804k used, 1982236k free, 167004k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
31791 apache 15 0 17272 5548 2396 S 0.0 1.1 0:00.08 httpd
27595 apache 15 0 17376 5492 2308 S 0.0 1.1 0:02.93 httpd
27601 apache 16 0 17376 5264 2120 S 0.0 1.0 0:00.43 httpd
2289 ntp 16 0 5140 5132 3440 S 0.0 1.0 0:05.08 ntpd
2758 root 16 0 13288 3148 1288 S

Re: memoryleak? oomkiller kills processes

Vitaly Karasik_1 — Sun, 20 Mar 2005 10:54:05 GMT

I suggest to run "top" via cron every 5 minutes, for example, so we'll able to see which process[es] eat memory.

Re: memoryleak? oomkiller kills processes

Chakravarthi — Wed, 23 Mar 2005 02:40:16 GMT

if you do not want to use top,
you can use
ps -aux command.

Re: memoryleak? oomkiller kills processes

Donald Kok — Fri, 25 Mar 2005 03:06:38 GMT

The system works ok now. I do not know exactly why, but it has something to do with:

- cronjobs starting when the previous version was not finished.
- the configuration of /etc/pam.d/crond
- the running of lots of mrtg-jobs

Re: memoryleak? oomkiller kills processes

Donald Kok — Fri, 25 Mar 2005 03:07:34 GMT

So this thread is closed.