[horde] Sessions consuming CPU

[Simon Wilson]

Simon Wilson
M: 0400 12 11 16

On 04/11/2011, at 5:51 PM, LALOT Dominique <dom.lalot at gmail.com> wrote:

> 2011/11/4 Simon Wilson <simon at simonandkate.net>
> Over the last few weeks I have noticed periods of time where the virtual server running Horde climbs to 100% CPU utilisation. This can last for hours.
> 
> Last time was 6 days ago, but then it did it again at 00:41am this morning, so I jumped into some troubleshooting.
> 
> Stop httpd and the CPU drops to 0. Start it again, and within a minute or two it hits 100% again, and stays there.
> 
> So I emptied the logs, stopped httpd, and set to monitoring it.
> 
> iPhones / iPads turned off, Imp logged out.
> Started httpd.
> httpd access_log for Horde remains empty, with ZERO incoming requests.
> After about 15 seconds this time - httpd hits 100%. AT THE SAME TIME, this message hits the horde log:
> 
> 2011-11-04T01:04:11+10:00 ERR: HORDE [imp] Server does not support TLS connections. [pid 22050 on line 340 of "/var/www/horde4/imp/lib/Imap.php"]
> 
> This message hits /var/log/horde up to 25 times per second, during which CPU usage remains at 100%.
> 
> Still no incoming requests for httpd in httpd/access_log, or errors in httpd/error_log.
> 
> The exact second that Horde logs that error, CPU hits 100%. Stop httpd, restart it, reproduce it. Did this several times over an hour, producing the exact same result - still ZERO http requests made of horde, 100% CPU at the same point the error gets logged.
> 
> So I logged in to Horde, and looked in "Sessions". About 30 sessions sitting in there, dating back up to a week old, across iPhone, Ipad, Mozilla, IE.
> 
> As soon as I deleted the session files from /var/lib/php/session (kicked me out of Horde as expected), CPU usage immediately dropped, and the IMAP TLS message stopped.
> 
> It hasn't done it this morning since, and clearing the old sessions has stopped both the errors in the log and brought CPU usage down to about 3%.
> 
> Is there any way I can stop this reoccurring (other than monitoring for 100% CPU load and triggering a session file delete!)
> 
> Thanks
> Simon.
> 
> --
> Simon Wilson
> M: 0400 12 11 16
> 
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> 
> There was a bug in imp 5.0.13. For some search, IE9 is looping and leads to 100% CPU. The new version 5.0.14 should be better. You don't tell your version..
> 
> 
> -- 
> Dominique LALOT
> Ingénieur Systèmes et Réseaux
> http://annuaire.univmed.fr/showuser.php?uid=lalot

Thanks Dom. 

Fully current and updated as at yesterday evening so not that tho. 

And there are no active Imp sessions anyway. :(

Simon