[horde] Session issues?

[Michael M Slusarz]

Quoting Michael M Slusarz <slusarz at horde.org>:

> Quoting Kevin Konowalec <webadmin at ualberta.ca>:
>
>>
>> On Aug 28, 2008, at 7:16 PM, Steve Devine wrote:
>>>>
>>> Whats this set for in horde/config/conf.php ?
>>> $conf['session']['timeout'] =
>
> [snip]
>
>> It is set to 0.  I haven't changed it from the default.  Is that a  
>> total session timeout or an inactivity timeout?
>
> For memcache, the important setting is 'session.gc_maxlifetime'  
> which is located in php.ini.  Although looking at the description,  
> this may not be the proper setting:
>
> session.gc_maxlifetime specifies the number of seconds after which  
> data will be seen as 'garbage' and cleaned up. **Garbage collection  
> occurs during session start.**
>
> For memcache, we have no control over when garbage collection  
> occurs, so using it in this manner for the memcache session handler  
> is not proper.  We probably need an explicit lifetime configuration  
> option in the memcache session driver.

This is what I came up with:
http://lists.horde.org/archives/cvs/Week-of-Mon-20080825/082646.html

Essentially, removed all lifetime calls from memcache driver because  
memcache doesn't care about garbage collection - it will gc  
automatically when the pool is full.  Thus, using  
session.gc_maxlifetime doesn't make much sense to use here.

A couple of other points, while on the memcache topic.  First, 6GB of  
memcache seems a little low for a decent sized installation,  
especially if using memcache as the caching driver.  Even if you have  
32-bit machines, you can still get 3GB+ per machine easily.  Or,  
better yet, take the splurge and buy a couple of cheap 64-bit boxes  
instead.  The great thing about memcache is that it doesn't need  
powerful, server-grade hardware to run.  In fact, that is overkill.   
Any cheap 64-bit box is going to be plenty powerful enough to handle  
the memcache load.  Quite honestly, your bottleneck will come from the  
network traffic to/from the memcache server/PHP server, and most  
likely the network infrastructure will be the limiting factor, not the  
network I/O speed on any given interface card.

Also, absolutely no reason to reboot memcache every night.  In fact, I  
highly recommend you don't, especially if you are caching with  
memcache also.  Rebooting simply loses all those hardearned  
mailbox/message caches that your servers labored to build every day.

This stuff should probably go in the wiki/FAQ.  But I've been dealing  
with the DNC all week and I am beat so maybe someone else could be  
kind enough to start a page and stick it up there.

michael

-- 
___________________________________
Michael Slusarz [slusarz at horde.org]