If there are white space on the Exchange 2007 databases, can Exchange server reuse that white space or it cannot until you defrag it? I really don't want to run defrag my Exchange databases becasue they are fine, no index corruption, is just that I have lots of white space. I don't want to move them to other empty databases because I have SCR enable on these Exchange databases.

Exchange will reuse the white space on its own. An offline defrag is not necessary. How much white space do you have? Is the server being regularly backed up? Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Sembee, I have 5 Exchange databases and the biggest white space is 6GB and smallest is 2GB. Yes, Exchange databases is being backup every night with Symantec Backup Exec 10.

Does that number change over time? How large are the databases overall? If the databases are 20gb then you have something to worry about. If they are 200gb then I wouldn't worry. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

The Exchange database that has 6GB white space is about 70GB. Is there article saying that Exchange will reuse the white space on the database?

That's basically the definition of white space (aka free space in the database) and the reason why the online maintenance goes through the trouble of freeing up space. The confirmation you are looking for is buried in here: http://technet.microsoft.com/en-us/library/aa996139(EXCHG.65).aspx (for Exchange 2003 but still generally applies to 2007.) I couldn't find a more succint official Microsoft source :) Is the physical size of the database (this means the size of the edb file) growing? To me, your situation doesn't seem unusual.