Coda File System

Re: is coda right for me? (mail servers)

From: Steve Simitzis <>
Date: Mon, 11 Oct 2004 18:06:24 -0700
On 10/11/04, Jerry Amundson <> wrote: 

> > Be aware that you cannot have a single directory bigger than several
> > thousand entries (directory size is limited to 256K I think).
> > It is probably the biggest concern for maildir-based installations.
> That might prevent me from pursuing this - we have several users with 
> maildir directories with over 5000 files, and one user each in the 
> 8000, 9000, and 10000 files ranges.
> If the limitation is "directory size", then the size of files needs to 
> be considered in conjunction with their numbers, right?

the way around this with coda is to implement a hashed directory
scheme with maildir, and change your MTA code to rewrite the file
names to include the hashed directories. (of course you would have
to create the hash directory buckets in advance or at the time when
you create the maildir.)

and so on.

otherwise a fairly average mailbox will be too large. another problem
with coda are directory conflicts. if two MTAs running on different
machines add a file to the same directory at the same time, it's
possible that it will generate a conflict. until you track down and
repair the conflict, the directory may be unavailable to the user and
mail delivery may be delayed. hashing can cerrtainly help with this

another problem with coda is that volumes seem to have an upper limit
of files that it can support. so you'll have to be careful about how
you arrange users into each volume.

though, if you're using maildir, why not just use NFS on top of reiserfs?
maybe NFSv4 running over tcp might be a good thing to check into.


steve simitzis : /sim' - i - jees/
          pala : saturn5 productions : 415.282.9979
  hath the daemon spawn no fire?
Received on 2004-10-11 21:10:04