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From Petr Hracek <phrac...@gmail.com>
Subject Re: [users@httpd] apache seems to be busy
Date Wed, 19 Oct 2011 06:52:34 GMT
Hello Tom,

as you mentioned I need to do stress test of the application.
How to do that for SSL connection?

best regards
Petr

Dne 18. října 2011 13:59 Tom Evans <tevans.uk@googlemail.com> napsal(a):
> On Tue, Oct 18, 2011 at 12:11 PM, Petr Hracek <phracek2@gmail.com> wrote:
>> Dear users,
>>
>> There are run most AJAX requests. After increasing the values
>> StartServers 15
>> MinSpareServers 10
>> MaxSpareServers 30
>>
>> ==> error_log <==
>> [Tue Oct 18 11:25:59 2011] [info] server seems busy, (you may need to
>> increase StartServers, or Min/MaxSpareServers), spawning 8 children,
>> there are 0 idle, and 23 total children
>> [Tue Oct 18 11:26:00 2011] [info] server seems busy, (you may need to
>> increase StartServers, or Min/MaxSpareServers), spawning 16 children,
>> there are 7 idle, and 31 total children
>>
>> Can there be a problem that AJAX objects did not close the connections properly?
>>
>> Thank you in advance
>>
>
> Anything is possible, but no, that is unlikely.
>
> Do you have more of these messages in the log? It looks like you don't
> start enough children to serve your peak load. These two log entries
> show that your server started with 15, and within a few seconds
> started an additional 16 children, indicating that you need to
> increase your StartServers.
>
> Forking isn't free, so you will want to start as many child processes
> as you will probably need, and allow them to stay alive rather than
> killing them off when you get quiet, just to respawn them again when
> you are busy. The trade-off from doing this is that each child
> consumes memory.
>
> Therefore:
>
> Set StartServers and MaxSpareServers to the same value, and increase
> both until you don't get these messages - we increase MaxSpareServers
> so that it doesn't just kill them all off in quiet periods.
>
> Once you have found how many server children you need, set
> StartServers to that value, MaxSpareServers to maybe 80% of that
> value, and MinSpareServers to about 10% of that value.
>
> The next step is working out how many server children is too many. To
> do this, you need to stress test your application, trying to get it
> super busy - basically, in fact, until Apache croaks that you need to
> increase MaxClients.
>
> Stop the test, increase MaxClients (if you increase it above 256, you
> also need to increase ServerLimit), repeat test. Do this until your
> server runs out of memory/CPU/disk - that is your absolute limit to
> number of server children. I'd normally step back a bit from that, to
> allow some overhead.
>
> As an example, one of our busy apache servers has StartServers 200,
> MinSpareServer 20, MaxSpareServers 160, MaxClients 512, ServerLimit
> 512. When we approach MaxClients, the box is approaching running out
> of memory.
>
> Hope that helps
>
> Cheers
>
> Tom
>
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-- 
Best Regards / S pozdravem
Petr Hracek

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