What is the best way to run offline defragmentation of Exchange 2003 mail store if you don't have enough disk space on the server. Can you attach an external drive and store the temporary defrag file and then just copy the defrag file to the path where the database is located.
You can redirect the temporary files to another drive using the /T option, or indeed if you really have to you can actually take the database files (you want the EDB and STM files) and the ESEUTIL tool and run it on another box which does not even have Exchange on. Obviously transferring everything all takes time while Exchange is offline, so this is a last resort. How to run Eseutil on a computer without Exchange Server
How much free (white) space do you have in the database? The online tools are pretty efficient normally unless you have done a big bunch of mailbox move or delete operations.