[horde] Too many httpd processes and no response

[Arjen de Korte]

Citeren ANANT S ATHAVALE <asa at isac.gov.in>:

> Dear List,
>
> I have released HGWE 5.1.3 to my users from last 3 days.
>
> We are facing unusual problem.
>
> When there is not much load, there is no problem at all.
>
> But, during peak hours of usage on a working day, suddenly too many httpd
> processes start and user gets no response.  Only solution is to restart
> httpd.  By this, there won't any issue for atleast one hour and problem
> repeats.

My first guess would be that you allow your server to spawn too many  
processes to serve the incoming requests. If this is more than the  
amount of memory allows, the result will be swapping and a dramatic  
decrease in performance. Users will try to reconnect then, worsening  
the problem. Which webserver are you using? If Apache, which MPM are  
you using?

> I am unable to diagonise this right now.
>
> 1. I have installed HGWE on RHEL 6.4
> 2. Using APC Cache as provided with RHEL

Is there enough memory available for APC? Look at the apc.php status  
page to see if there is sufficient memory available, especially if  
you're using it as a caching backend.

> 3. Using PHP 5.3.3-27 as provided with RHEL
> 4. Using SquirrelMail IMAP proxy latest stable version, compiled on the
> same server.
> 5. Using Cyrus-IMAP server on a remote server and following string logged
> in Horde-IMAP debug log
>
> S: * OK [CAPABILITY IMAP4rev1 LITERAL+ ID ENABLE  XIMAPPROXY]
> newisacmail.isac.dos.gov.in Cyrus IMAP v2.4.17-Invoca-RPM-2.4.17-6.el6
> server ready

Have you enabled IMAP caching in imp/config/backends.local.php?

> I am unable to debug why httpd suddenly starts too many processes.  I have
> already enabled DEBUG log in Horde conf.php

Definitly don't do this. Your investigating a performance problem  
here. Logging at level DEBUG will generate tons of information and on  
a busy server this will be enough to bring it to its knees.

> Can anybody suggest, how to go about debugging further and come to some
> conclusion.
>
> And to add, I have all pre-requisite installed.  I have already disabled
> thumbnail view to avoid high loads of CPU.  Will enable only after
> resolving the main issue.
> -- 
>           Regards
>            Anant
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