[horde] Cache System Questions

Michael M Slusarz slusarz at horde.org
Thu Dec 18 21:08:55 UTC 2008

Quoting Kareem Dana <kareem.dana at gmail.com>:

> I have a few basic questions mainly about the caching options in
> Horde. Thanks for any clarification.
> 1) Cache System: I have it set to Store objects in filesystem. I can
> use the SQL based cache. Performance wise is one driver better than
> the other?

Depends on your system.  The more important distinction is that it is  
easier to set up Caching across multiple systems with a non-filesystem  
based solution (although NFS and SMB may be used).

> 2) In /tmp I see lots of cache_<hashed id> files. I presume these are
> the cached objects. Does horde automatically clean these files up? Is
> it safe to run through them with something like tmpwatch and delete
> them after a week or so?

Yes and no.  Some code does do GC, and some doesn't.  If using  
filesystem caching, you will want a cron job to clean out the files  
every once in awhile.

> 3) Virtual File Storage: What is this used for and are there any
> serious differences between filesystem vs. SQL driver?

Used for storing persistent data.  Same differences as Cache driver above.

> 4) In Turba, I can select a VFS driver to use. Currently it is set to
> None and turba seems to be working fine. What does Turba use the VFS
> for?

Off the top of my head, I don't know.

> 5) In Imp, I can use the msgcache and/or the mlistcache. With msgcache
> what details are cached and approximately how much storage space is
> used per message?

Envelope/header/structure information.  Again, the amount of storage  
space per message is totally dependent on the typical types of  
messages received, and also depends on other factors such as whether  
IMP previews are enabled, the size of these previews, etc.


Michael Slusarz [slusarz at horde.org]

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