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From P J <>
Subject Re: [users@httpd] Help troubleshooting performance issue, after "1000 total children" Apache no longer responds to HTTP requests. Not MaxClients issue?
Date Thu, 03 May 2012 18:29:52 GMT
On Thu, May 3, 2012 at 9:51 AM, Pablo Armando <>wrote:

> What about the number of open file descriptors ??
> On 05/03/2012 01:33 PM, Tom Evans wrote:
>> On Mon, Apr 30, 2012 at 4:20 PM, P J<>  wrote:
>> .... The fact that your issue seems to happen when you go above 1024
>> clients - a magic number - suggests that it may be something
>> programatically wrong. Hope that helps!
> Thanks for the great feedback everyone, much appreciated.

Tom: I will check the listen queue the next time this happens to see how
large it is.

Good idea about raising the limit to accommodate the peak as a starting
point, I've switched it to:

StartServers     500
MinSpareServers  1024
MaxSpareServers 1024
ServerLimit     3500
MaxClients      3500
MaxRequestsPerChild  4000

Then in the error log I'm seeing:

[info] server seems busy, (you may need to increase StartServers, or
Min/MaxSpareServers), spawning 32 children, there are 1003 idle, and 1043
total children

How can the "server seems busy" with 1003 idle children? yet it is spawning
32 more children? Am I totally missing something obvious here?

Also a great idea to test with the 2.2.22 instead of the OS supplied 2.2.3,
I will look into that for sure.

Pablo, open file descriptors was originally what I thought the problem was,
but I raised them from 1024 to 16384 and it made no difference:

cat /proc/$(pidof -s httpd)/limits
Limit                     Soft Limit           Hard Limit           Units

Max cpu time              unlimited            unlimited            seconds

Max file size             unlimited            unlimited            bytes

Max data size             unlimited            unlimited            bytes

Max stack size            10485760             unlimited            bytes

Max core file size        0                    unlimited            bytes

Max resident set          unlimited            unlimited            bytes

Max processes             55296                55296
Max open files            16384                16384                files

Max locked memory         32768                32768                bytes

Max address space         unlimited            unlimited            bytes

Max file locks            unlimited            unlimited            locks

Max pending signals       55296                55296                signals

Max msgqueue size         819200               819200               bytes

Max nice priority         0                    0
Max realtime priority     0                    0

Thanks again.


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