Released: v14.4 of the Exchange 2010 Mailbox Server Role Requirements Calculator

A while ago I used the Mailbox Role Calculator for sizing a small environmentl. Because of some political posturing three companies must be divided over three databases. The smallest one was 25 users with a Mailbox Size limit of 1024 MB. The LOG LUN requirements

for this database was proposed as a 1GB LOG LUN. But this will not work.

When the Exchange store detects that the space available on a log or database drive is below 1 GB, it cuts off all transport delivery to that database. This is to prevent a disk running out of space. When a disk runs out of space, the database can't be mounted

or debugged. The database space also can't be reclaimed. This is a self-protecting mechanism that only occurs if you don't react to the space issue warnings from your monitoring infrastructure.

When the disk space goes above 1.5 GB, the Exchange store allows deliveries to continue.

Check: http://technet.microsoft.com/en-us/library/bb331958.aspx#Low

http://technet.microsoft.com/en-us/library/bb331958.aspx#Low

So the minimal size for a LOG LUN must be increased.