The backup plugin was deprecated in 0.4.x, below are backup recommendations for 0.5.x and later.
Because Dokku is git based, rebuilding a deployed app is as easy as pushing from git. You can push to a new server by updating the
dokku remote in you local app's repo.
git remote rm dokku git remote add dokku dokku@[dokku.me:dokku.me] git push dokku [master]
Some plugins, like the official dokku-postgres plugin, have built-in commands that allow non-volatile data be exported and imported.
For dokku-postgres, use:
dokku postgres:export [db_name] > [db_name].dump dokku postgres:import [db_name] < [db_name].dump
Dokku doesn't enforce a 300mb limit on apps, but it's best practice to keep binary assets outside of git. Since containers are considered volatile in Dokku, external stores like s3 or storage mounts should be used for non-volatile items like user uploads. The Dokku storage core plugin can be used to mount local directories / volumes inside the docker container.
See the persistent storage documentation for more details.
The best plan for disaster recovery is to always keep multiple (remote) copies of your local repo, static assets and periodic database dumps. In case of an emergency when your git repo and backups are completely lost, you can recover the last pushed copy from your remote Dokku server (assuming you still have the ssh key).
mkdir [app-name] ; cd !$ git init && git remote add dokku dokku@[dokku.me:app-name] git pull dokku/master && git checkout dokku/master