Offline defragmentation creates a new database by copying all records and tables from the old database into the new database . Because this is a copy, defragmentation requires free disk space equal to the size of the database (actually, you'll need 110% of free space).
Microsoft recommends a conservative 5 - 7 GB per hour for a defrag operation, which means that your server will be offline for as long as it takes, assuming no hardware failures will occur.
Sr. Systems Administrator, MarkMonitor
391 N. Ancestor Pl. Suite 100
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From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Danny
Sent: Thursday, November 15, 2007 10:10 AM
Subject: [ExchangeList] Exchange offline defrag timeframe
Any idea how long and how much disk space I will need to offline defrag the following platform?
Server: Xeon 3.6Ghz, 4GB RAM, RAID 5 on 4 15K RPM SAS drives
Exchange Server 2003 SP2
Primary Storage Group = 90GB
Secondary Storage Group = 15GB