There are several things to backup if you want a full backup/restore.
incomplete/complete directories and files. These should be specified in your transmission-daemon settings.json (location depends on your install but defaults to
$HOME/.config/transmission-daemon/settings.json on linux I think).
Your source torrent files may also be getting "picked up" from a watch directory somewhere but you don't generally need to keep these. If you want to keep these you should back this up as well. Directory location also specified in your
settings.json. However transmission is often configured to delete source torrent files (from watch dir) after they are added.
The "state" for transmission-daemon is stored in
$HOME/.config/transmission-daemon/ so aside from your partial/complete download folders, this is the important folder to grab if you want to resume in-progress downloads after backup is restored on a new install. Note that
$HOME in this case will be whatever
$HOME is for the
transmission-daemon process and may not be your own user's home directory. This location can be overridden by starting
transmission-daemon with the
--config-dir param (see
[root@some-server current]# find /root/.config/transmission-daemon/ -type f
Be warned that the torrent/resume files in the config folder expect the downloads/incomplete files to be in a specific location...so if you change the OS path where you are storing incomplete and complete downloads you will need to start transmission and then tell transmission where to find the files.
For complete (torrent number 3)
transmission-remote -t 3 --find /new/path/to/complete/downloads/
For incomplete (torrent number 4)
transmission-remote -t 4 --find /new/path/to/incomplete/downloads/
If you keep complete/incomplete in the same directory then it is easier as you can update all torrent locations in one go.
For complete/incomplete (all torrents)
transmission-remote -t all --find /new/path/to/downloads/
I found (with Transmission 3.00) that even if you tell transmission where to find the files and see that
transmission-remote -t <torrent-id> -i now reports the updated location...there is still an error message about not finding any data. You need to restart transmission-daemon for it to re-scan the new location, find the data and stop reporting an error.
You should also make sure to
chown -R all the config/download files to the user the transmission-daemon process is running as if you change the user.