[EP-tech] Re: Eprints Server Freezes Often

Sebastien Francois sf2 at ecs.soton.ac.uk
Tue May 22 12:50:21 BST 2012


Hi,
> Its been almost 24 hours since I made the changes in the apache config
> file. What I have noticed after the changes is that the number of httpd
> processes is averaging less than 30. Before making the changes in config
> file, I have noticed that at times the number of httpd processes would be
> 130+. That's when the server would freeze.
>
> So, the changes in the config file is keeping the number of httpd process
> under control. However, just a while ago, I noticed that the eprints
> server was taking a long time to respond. I checked the number of httpd
> processes, there were 22 of them and the 'top' command produced the
> following output:
>
> top - 17:03:33 up 5 days,  5:17,  1 user,  load average: 2.94, 3.55, 2.80
> Tasks: 167 total,   2 running, 165 sleeping,   0 stopped,   0 zombie
> Cpu(s): 25.6%us,  0.6%sy,  0.0%ni, 49.2%id, 24.6%wa,  0.0%hi,  0.0%si,
> 0.0%st
> Mem:   4051536k total,  4025724k used,    25812k free,     5304k buffers
> Swap:  8193108k total,  4098224k used,  4094884k free,    66116k cached
>
> There is clear indication that the  free memory is quite low. I restarted
> the httpd server and the output of the 'top' command right after the
> restart is:
>
> top - 17:05:57 up 5 days,  5:19,  1 user,  load average: 12.27, 6.11, 3.78
> Tasks: 160 total,   1 running, 159 sleeping,   0 stopped,   0 zombie
> Cpu(s):  2.2%us,  0.2%sy,  0.0%ni, 92.8%id,  4.8%wa,  0.0%hi,  0.0%si,
> 0.0%st
> Mem:   4051536k total,   335168k used,  3716368k free,     7644k buffers
> Swap:  8193108k total,   263748k used,  7929360k free,    69500k cached
>
> More than 3.5GB of main memory has been freed after the httpd restart. Is
> there anything else that needs to be done to maintain the optimal memory
> level to ensure that the eprints server response level is consistent?
>
> Thanks for your attention, Francis
>
Your server is using a lot of swap (4GB) so this will definitely slow 
things down a lot.

Check the memory size of a single apache process, and limit the max 
number of processes so that apache doesn't take over your entire memory 
(leave some for mysql and other services..).

As for your mysql connections, EPrints should use one mysql connection 
per process so make sure mysql has more connections available than there 
are apache processes running.

Seb.





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