Back Up and Restore Docker Volumes

Why back up volumes

Containers come and go, but the data in a Docker volume stays. A volume can still be lost if the disk fails, someone deletes it by mistake, or a move to a new server goes wrong. A backup lets you rebuild the data in minutes.

Back up a volume

The idea: start a small temporary container, attach the volume, and pack its content into a .tar file on the host.

docker run --rm \
  -v my_volume:/data \
  -v $(pwd):/backup \
  alpine tar czf /backup/my_volume.tar.gz -C /data .

• my_volume is the name of your volume. List volumes with docker volume ls.
• The file my_volume.tar.gz appears in the folder where you ran the command.
• The container is deleted after the job (--rm).

For a database, stop the container first or use the dump tool of the database. This way the backup is complete.

Restore a volume

1. Create a new volume:

docker volume create my_volume_restored

1. Unpack the archive into it:

docker run --rm \
  -v my_volume_restored:/data \
  -v $(pwd):/backup \
  alpine tar xzf /backup/my_volume.tar.gz -C /data

1. Attach the volume to a new or existing container with -v my_volume_restored:/path/in/container.

Automate it

A hand-made backup is fine for tests. For production, run it on a schedule.

• Put the backup command in a script and run it with cron.
• Add a clean-up step that deletes old archives.
• Many hosting platforms also offer snapshots.

Good habits

• Back up on a fixed schedule.
• Store copies off the server, such as on another host or in cloud storage.
• Test a restore from time to time. A backup you never tested may not work.

Quick recap

• Use a temporary container with tar to back up a volume.
• Restore into a new volume with the same method.
• Automate, keep copies elsewhere, and test.