IMAP server alternatives

[Greg Groth]

On 7/11/2006 9:29 AM, albi wrote:
> Erik Norgaard wrote:
> 
>> Regarding cyrus documentation: I think they have stopped maintaining the
>> documentation and moved to use the wiki - unfortunately, you don't
>> stumble into the wiki first :(
> 
> i can happily recommend Dovecot, really easy to install (Cyrus really
> isn't), supports both Maildir and mbox, been using it for years without
> any problems (i used courier before that, but i like dovecot much better)
> 
> see here :  http://www.dovecot.org and
> http://wiki.dovecot.org/

I would like to ask a couple more in depth questions pertaining to this 
conversation.  We recently switched from POP3 & Outlook Express to IMAP 
using IMAP-UW & Thunderbird.  Personally I have had no issues with 
IMAP-UW, but the users in our office have had issues with the mbox 
format itself.  Specifically they cannot store messages & subfolders 
within a folder (referring to the Thunderbird definition of a folder). 
In mbox, since a given folder is not a directory, but a file, you cannot 
place a subfolder within that file.  Outlook Express' POP3 
implementation did not have this behavior.  Right or wrong, my users 
have requested that I attempt to restore this functionality in IMAP.  Am 
I correct in assuming that if I switch to a mdir format server, it will 
operate in the manner they are requesting?

My next question is in regards to scalability, not so much in the way of 
users, but in the amount of mail they store.  Currently we have about 20 
email accounts, and for the most part the users keep their email to a 
reasonable amount.  However I do have 5 users that insist they save 
everything, and do not clean out their InBoxes.  Currently they retain 
email going back 5 years, and have mail folders in excess of a couple of 
gigs apiece.  Since one of these people is the owner, I have little 
chance of changing this policy.  However they are asking that I attempt 
to increase the response time of the IMAP server, which can be somewhat 
slow for them - especially through SquirrelMail.  Would the mdir format 
help in this situation as well?

Last question, how difficult is it to back up the mdir format? 
Currently I cron a tar job, nightly, to backup the mboxes to another 
server to allow for tape backups (the tape unit on the server in 
question doesn't want to play nice with FreeBSD), and have had no 
difficulty in accomplishing this.  Can I accomplish the same style of 
backups when moving to mdir?

I'm in the middle of setting up a server to try out various IMAP servers 
to test which would provide the best response for our specific needs 
(low number of users - high volume of saved email), and would appreciate 
any opinions on the matter as it would probably save considerable time 
picking the right software to begin with.

Best regards,
Greg Groth