Tunning for large number of files in INBOX

Michael Loftis mloftis at wgops.com
Wed Jun 29 16:56:58 EDT 2005

--On June 29, 2005 4:30:06 PM -0400 Joel Nimety <jnimety at perimeterusa.com> 

> Hello,
> I'm trying to set up cyrus-imap as a backend for an email archiving
> solution.  I'm creating one account on the imap server for each customer
>   domain(s) we'll be archiving mail for.  I'm concerned that the number
> of emails that will end up in each INBOX will reach some limit (ext3 fs
> limit, practical limit, etc.)

With EXT3 there are definite limits, not hard ones, but practical ones for 
time to traverse/read the inode and list.  Use ReiserFS.  For Mail clients 
most can't handle big folders because many of them are just POP3/NNTP 
clients retrofitted to squak IMAP.  Get a real IMAP client like Mulberry 
that takes advantage of server side sorting, threading, and searching to 
allow for (nearly) limitless mailboxes but not download each and every 

With ReiserFS and UFS+Hashdirs (Linux and FreeBSD respectively) I 
personally have many mailboxes that are well over 20k or 30k messages, and 
have a few in the 200k range, haven't run into any performance problems. 
With EXT3 I had serious problems in the 5k range, or less.

> Is there a way I can have cyrus hash the files within the INBOX
> directories into sub directories? If this isn't possible does anyone
> have a sieve script that can sort mail into folders by date?  Any help
> is much appreciated.

No, and no, but the latter should be something simple enough to 
create.....A coworker did something llike this and found he had to create 
entries for every month, and then either manually swap them yearly or 
rewrite the rules yearly because Sieve has no variables or anything like 

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