All you have to do is:
1. Copy all files over to another, empty partition. This new partition is now defragulated.
2. You can now delete everything off the first partition, then copy everything back if you like.
Works on every Amiga with any amount of RAM.
I suggest adding some buffers using the AddBuffers command before you do your mass copy because it will speed things up a lot. If you have the RAM you can do AddBuffers 1000 to both source and destination drives.
This idea works even better when you have 2 separate hard drives. There is less head-thrashing that way so the copying goes much faster.
Or if you use a solid state hard drive that eliminates the head thrashing also.