Have our primary post office on a sles11sp3 / oes11sp2 box. Currently
have just over 210 users and 20 resources on this POA. Server also
runs our primary MTA.

Volume for post office and primary domain is nss and ~200GB in size.
The mail volume on this box is down to just over 17GB free. About how
much more free space can be lost before I start seeing POA / MTA errors
due to space issues?