How do I move ALL my Torrent data to an external drive?

[TranTran]

There must be a way to move everything in a batch fashion, I can't "Move Data File To" on hundreds of files.
And a lot of these are active files, trying to finish a download or actively seeding.
Step by step instructions anywhere?

And if I ever activate Transmission when that hard drive is not connected -- will it fail cleanly, or do something catastrophic like create a mirror of the expected location on the root internal drive & lose the connection to the actual data? Some years ago it did the latter, according to a forum thread I found.

[TranTran]

Here's a thread explaining the catastrophic failure:
viewtopic.php?f=4&t=9771&p=75412&hilit= ... %3A#p75412

[darmok]

Pause the torrents.
Select the torrents.
select "Move Data File To..."

You can do the move while the torrents are running, but then it will take much much longer to complete.

Once you've moved things, if you launch Transmission without the HD connected, the torrents will complain. Just quit Transmission; no harm done.

- Dan.