[horde] apache cpu usage?

[Arjen de Korte]

Citeren avp at rokeyetee.com:

> Quoting Michael J Rubinsky <mrubinsk at horde.org>:
>
>> Quoting avp at rokeyetee.com:
>>
>>> I'm running Horde on a AWS t2.medium instance - HORDE GROUPWARE WEBMAIL
>>> EDITION 5.2.6
>>>
>>> I've got some funny apache behaviour that just doesn't seem right to
>>> me...
>>>
>>> When I run "apache2ctl status", 99% of the time all threads are in the
>>> "W"
>>> (Sending Reply) state:
>>>
>>>    Current Time: Thursday, 18-Feb-2016 10:02:53 NST
>>>    Restart Time: Thursday, 18-Feb-2016 09:49:25 NST
>>>    Parent Server Config. Generation: 1
>>>    Parent Server MPM Generation: 0
>>>    Server uptime: 13 minutes 27 seconds
>>>    Server load: 0.77 0.77 0.85
>>>    Total accesses: 1382 - Total Traffic: 7.7 MB
>>>    CPU Usage: u230.64 s11.47 cu0 cs0 - 30% CPU load
>>>    1.71 requests/sec - 9.8 kB/second - 5.7 kB/request
>>>    20 requests currently being processed, 8 idle workers
>>>  
>>> _WWWWWW_WWWWW__W_WWWWWW__W.K_...........
>>>
>>> It seems strange to me that "sending reply" would be the bottleneck?
>>>
>>> Also when I run top, I constantly see apache procs jumping to the top
>>> with
>>> up to 50% cpu usage.
>>>
>>> Most all the connections are ActiveSync.
>>
>> When an ActiveSync client is configured for "Push", the connection to
>> the webserver remains open while it runs the PING command. These
>> requests last up to the "hearbeat interval" that is negotiated between
>> the server and client unless there is a change detected, when the PING
>> requests ends and a new SYNC request is issued. It makes complete sense
>> that you would see ActiveSync connections remaining open.
>
> Thanks for the quick reply.
>
> I'm not questioning that the ActiveSync connections remain open - I  
> get that.  I'm questioning that the connections are in the "Sending  
> Reply" state?  And that my CPU usage seems too high to me?  I'm  
> wondering if there is some php being called to generate the reply  
> that is being sent but it is taking abnormally long/excessive cpu?   
> Just sort of guessing here...  How might I track down what is using  
> the cpu or why the connections are in the sending state?
>
> Here are my activesync settings:
>
> $conf['activesync']['ping']['heartbeatmin'] = 60;
> $conf['activesync']['ping']['heartbeatmax'] = 2700;
> $conf['activesync']['ping']['heartbeatdefault'] = 480;
> $conf['activesync']['ping']['deviceping'] = true;
> $conf['activesync']['ping']['waitinterval'] = 10;
>
> I just changed waitinterval from 5 to 10.

That is still an awfully short interval. It will mean that the PHP  
process that is kept active for each device that is connected through  
ActiveSync will poll the users mailbox every 10 seconds. Depending on  
the number of users you have, this may constitute a fairly significant  
load. Note that if you have a decent IMAP server such a short interval  
is a waste of effort anyway, as the IMAP server will notify that  
things have changed.

> Any suggestions on what these should be?

If you have a significant number of users connected through  
ActiveSync, increase waitinterval to something like 60 seconds (or  
more).

> Any other tips/advice to lower CPU usage?

Which IMAP server are you using and how many ActiveSync devices do you  
have connected?

> Thanks again.
>
>>
>>> What are recommended settings for apache when running Horde?
>>>
>>> Any other tips/advice to lower CPU usage?  
>>> Thanks.
>>>
>>>  
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>>
>> --
>> mike
>> The Horde Project
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>
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