[Dovecot] Dovecot suggestions for new installation

[Timo Sirainen]

On Jan 13, 2009, at 10:45 AM, Michael Durket wrote:

> I've been testing Dovecot for a while now and am preparing to  
> replace our outdated IMAP
> system with it. The current system serves about 300 email users who  
> run a mixture of
> clients (Eudora, Apple Mail, Thunderbird and Outlook). Can any of  
> the many experts on
> this list answer a few questions:
>
>    1) What's the latest stable release of Dovecot I should be  
> running on this new system
>         (Dovecot will be running on a RedHat Linux AS 4 64 bit  
> system with plenty of memory
>         and CPU). I've been running 1.13 on my test system but I see  
> that 1.18 just came
>         out (although I don't know if I should switch to it  
> immediately.

I recommend 1.1.8. Especially if you're planning on using mbox format,  
since it fixes several bugs related to it.

>    2)  What configuration file options (if any) should I turn on to  
> best handle the range of
>          email clients listed above?

Look at the imap_client_workarounds setting and enable the ones you  
need.

>    3)  Are there any "sizing" options I need to worry about setting  
> for the number of
>          email users I have (I suspect that 300 users is considered  
> a rather small
>         mail system but I want to minimize its resource usage as  
> much as possible
>         while still giving decent performance from Dovecot).

Not really. The default options should be fine for that. Anyway see http://wiki.dovecot.org/PerformanceTuning

>   And, just out of curiosity, I'm looking into the idea of switching  
> users from mbox format
> over to Maildir format on this system (it will use all locally- 
> connected disks and have no
> NFS mounts). Does the Dovecot automatic migration program to migrate  
> from mbox
> to Maildir work well or are there "gotchas"?


It doesn't preserve message UIDs, which causes clients to redownload  
them. This isn't such a big deal with IMAP, but if you have any POP3  
users that could be a problem (although you should make sure  
pop3_uidl_format is correct in any case).

I'd anyway recommend using one of the scripts that preserves UIDs,  
just in case. http://dovecot.org/list/dovecot/2008-March/029736.html  
apparently should work.

Also you should configure Dovecot to use '/' as the namespace  
separator for maildir too. Some clients don't like it when the  
separator changes unexpectedly. Also the '/' is more "standard"  
anyway. You might also want http://wiki.dovecot.org/Plugins/Listescape  
to allow using '.' characters in mailbox names, which you might  
already have.