[Dovecot] quota calculating

[Scott Zahn]

Hey everyone,
     Currently where I work we use qmail.  Every time a message is delivered,
qmail seems to walk through the user's entire maildir in order to
calculate quota usage.  Delivering messages simultaneously to just a few
users who are allowed large maildirs (1-2GB) will bring our servers to
their knees.  Which brings me to dovecot.  I use dovecot whereever I can,
but haven't yet needed to set up quotas.  I would like to migrate my
servers at work to use dovecot, but have a few questions regarding
quotas.  Could someone explain how dovecot calculates quota usage on mail
delivery?  Also, is there anyone here on the list that uses quoatas on
large maildirs (>=2GB)?  How well has it worked for you?

thanks,
Scott