Hashing directories - when is this recommended?

[freakysid]

I am writing some scripts that are going to cache output into files which will need to be stored together into directories. The directories will be created dynamically by the script. Then daily I am going to run a cron job to delete the cached files (and directories). This is on a i686 running RedHat 7.1

So. I am just wondering, is there a rule of thumb for working out what the optimal hashing scheme is for directories in the files system???

For example, if I expect to create say 1000 directories all under the cache-data directory, what level of hashing should I use for the directory structure?

None? One level, two, ...? Is there an algorithm? I'm not very good with data structures such as trees.

[MattR]

What do you mean? I'm confused, the only hashing I know is for indexing and hash functions.

[freakysid]

OK well my ignorance is shining through. I'm not talking about anything complicated like messing with the actual file system itself (its ext2 BTW). Just that I know that in general when you are creating, say lots of virtual server doc roots or virtual maildirs, etc, you often "hash" them out (if hash is the correct term to use in this context) using a crude method.

Example,

a/
   abanathy/
   almond/  
   apple/
/b
   bah/
   banana/
   boobies/

etc

Add another level to the hashing:

a/
  ab/
    aboriginie/
    abooboo/
  al/
    almond/
    alarmist/

 etc

So, there must be some rule of thumb or algorithm that ppl use here to decide to what level of hashing out of directories produces the optimal balanced tree strucure in the file system.