[Dovecot] Maildir and counting inodes

[Jon Roma]

Andy Cravens <acravens at uen.org> wrote:

> I've been testing with alpha 3 and I am about ready to go production.  I
> am switching from mbox to maildir and I'd like to know if there is a
> formula or rule of thumb for determining if your file system will have
> enough inodes to handle all the mail message files.
>
> I could write a script to look at each user's mbox files, count the
> number messages and calculate the average number of emails per user, then
> add a fudge factor for expected growth.  However, I doubt anybody
> actually goes to this much trouble to plan ahead.  Or do they?
>
> I'm running Solaris 9 and when I created the file system I just used the
> defaults.  If I need to change anything, I'd rather do it before going
> production.  Thanks for any info you can provide on this subject.

I've been down this path before -- I recently completed a transition
from UW IMAP to Dovecot and from mbx files to maildir -- in other words
from about 160 GIGANTIC files to zillions of tiny files.  The aggregate
size was just slightly over 2 gigabytes.

I used a fragment size of 1024 and a NBPI (number of blocks per inode)
of 2048 and find that I didn't quite achieve the balance between blocks
free and inodes free that I'd wanted.  Not a big deal since I don't have
hundreds of users and can always copy the filesystem if I feel compelled
to deal with the inode count.  So if this isn't as easy for you, you'll
probably want to do better than my SWAG.  In any case, I probably
underestimated the number of files with large attachments in my own mail
archive.