For one of my clients I'm currently migrating there old SharePoint 2003 Portal to the new Moss 2007 environment.
We are using the gradual upgrade procedure, this is the most safe procedure but also uses a lot of diskspace.
I did an upgrade of a WSS site of 32 GB, I monitored the diskspace usage:
- 32 GB for the content database datafile
- 41,4 GB for the content database logfile
- 82,8 GB for the temp datafile
- 42 GB for the temp logfile
TOTAL = 198,20 GB for an upgrade of 32 GB
That's "orginal content" x 6,19 = "diskspace needed for the upgrade"
So be sure you have enough diskspace before you start your upgrades!
After the upgrade the temp db is automaticaly deleted and you can shrink the log file of the content database on the SQL Server to free up some diskspace.