User directory hashing

[Jure Pe_ar]

On Thu, 17 Feb 2005 16:56:57 +0100
Tucsek János <tucsi at cyber.hu> wrote:

> Hi,
> 
> Does anybody know, how to turn on directory hashing on users directory?
> So, for example:
> Our user's messages are in: 
> 
> /imap/domain/foobar.com/user/foo
> .
> .
> /imap/domain/foobar.com/user/bar
> 
> directories.
> 
> And the question is: is there any directory hashing patch to cyrus ( 2.2+
> version ), what will make something like this with directories:
> 
> /imap/domain/foobar.com/user/f/fo/foo
> .
> .
> /imap/domain/foobar.com/user/b/ba/bar

Hm? hashimapspool: 1 in imapd.conf gives me this:

/imap/domain/f/foobar.com/b/user/bar ... which is ok, for now.

> Because we have approx. 20-25 thousand user under one domain dir (free
> mail service),

same here :)

> and when doing a backup it tooks a lot of time to get the directory
> listing...

Which filesystem? default ext3 is going to take some time here, yes ... 

Also, the next limit you're going to hit is 32k subdirectories per directory
max on many filesystems (at least ext2/3 and veritas behave that way).
Luckily, reiserfs does not suffer from this.


For those who don't (want) / can't use reiserfs and fulldirhash is too messy
... it would be nice to hash in the f/fo/user/foo way ... maybe like
something postfix does with the hash_queue_depth. Anyone?


-- 

Jure Pečar
http://jure.pecar.org/

---
Cyrus Home Page: http://asg.web.cmu.edu/cyrus
Cyrus Wiki/FAQ: http://cyruswiki.andrew.cmu.edu
List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html