I have a new client whose Exchange Server 2003 database size is approaching the 75GB size limit that is in place. Some users have large mailbox sizes and I have advised them to auto archive. Once this has been done I obviously need to decrease the size of the Exchange database to prevent it dismounting. Two questions: 1. Is it possible to find out what free space would be created as a result of a defrag of the database? 2. Presumably only a defrag will free up the space? 3. Can the space be freed up by an ONLINE defrag or must it be OFFLINE?

Hi, After online maintenance has run an event 1221 will be logged in the application log - this event tells you how much white space there is inside the database. If you do have a lot of white space (and monitor this) there should be no need to run a defrag as the white space will be used before the database grows again. Only an ofline defrag will shrink the database - and it will take a lot of hours to finish - 8 hours if you are lucky Leif

The database limit is a logical, not a physical limit. Therefore it is perfectly possible to go over 75gb in physical size and the database continues to work. The limit is the physical size, minus the white space. What this means is that an offline defrag is not always necessary. However long term, if you are approaching the limit you need to take steps to deal with it. This basically comes down to: a. Invest in an archiving product to remove content from the database. b. Upgrade to Exchange 2007 or higher, which supports effectively unlimited databases in standard edition. I have seen places run a script to remount the database every morning (it checks at 5am by default) to allow the size to be exceeded. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

cheers First things first they're going to do some archiving and store these so that they are backed up. There are some users with big mailboxes (15GB+) who have emails going back a long time, with some big attachments. I added up the total size of all mailboxes and it comes out at around 84GB. There are also some mailboxes that I've been asked to delete - all over 12GB each. Will see what happens to the size when this has been done and the auto online defrag is completed.