[horde] Memcache issue

Michael M Slusarz slusarz at horde.org
Fri May 23 17:51:56 UTC 2014

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

> APCu is a user cache, but it is a *shared* user cache, which isn't  
> useful for application-level caching (since it will quickly be  
> filled with data if used that way).  IIRC, it is not used by  
> anything in Horde other than the autoloader cache.

I am mistaken.  APCu (and older versions of APC) can be used for  
caching.  But I personally wouldn't recommend.  Some issues:

1.) Caching solution is only available on a single machine.
2.) Very limited sizes.
3.) I believe there are issues with fragmentation the way it stores  
data in shared memory.

If you have a single server (and are running a Ubnix-y machine),  
you'll get much better performance by doing something like creating a  
tmpfs filesystem and using that with the file cache driver.  Nice  
things about tmpfs, vs. APCu, is:

1.) You are having the kernel do memory management directly, rather  
than having an application do it (just more abstraction).
2.) tmpfs allows old, unused cache data to be swapped out onto disk if  
the OS needs additional memory in the future.  APCu storage is locked  
into memory IIRC.


Michael Slusarz [slusarz at horde.org]

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