[horde] Session issues?

[Kevin Konowalec]

On Aug 29, 2008, at 11:00 AM, Michael M Slusarz wrote:

> Quoting Kevin Konowalec <webadmin at ualberta.ca>:
>
>> 6 Gigs is low?  That likely explains part of the problem.  I was   
>> under the impression that with the new version of horde the  
>> session  data written to memcache was significantly smaller than  
>> the previous  version (I could have sworn I read session data was  
>> around 1MB per  user).  I've got a bunch of machines ready to go  
>> that will  essentially double my memcache pool - does 12 Gigs seem  
>> reasonable  for a big installation or should I find more?
>
> 6 Gigs is low if you are using memcache for both session handling  
> and caching.  6 Gigs should be plenty if just using session handling  
> alone.  But cache data can build up in a hurry - given that a  
> mailbox with 100 messages would produce cache files of at least 300  
> KB (and that is if using compression), multiply that by the number  
> of users and the number of mailboxes each user visits on a regular  
> basis and your cached data grows quite large.
>
> With 6 Gigs, you probably won't run out of space for your session  
> information, but your cached information might be lost for a user  
> that logs in once every day due to the last-used/first-out garbage  
> collection algorithm.  If that cached information is still available  
> on the next login, it will increase initial loading times  
> significantly.
>
> michael
>
> -- 
> ___________________________________
> Michael Slusarz [slusarz at horde.org]
>
>



Aaaaaaah that makes a lot of sense.  Wouldn't have thought of that.   
What's a recommended size if you're going to be caching?  Is there a  
significant advantage to having caching turned on or would users  
likely not notice the difference?

Thanks

Kevin