zfsbackrest

⚠️ Experimental:
Do not use it as your only way for backups. This is something I wrote over a weekend. There's a lot of things that need work here.

pgbackrest style encrypted backups for ZFS filesystems.

Getting Started

Installing

You need age installed to generate encryption keys. Encryption is NOT optional.

$ go install github.com/gargakshit/zfsbackrest/cmd/zfsbackrest@latest

Configuring

Create /etc/zfsbackrest.toml.

debug = true # warning, may log sensitive data

[repository]
# zfsbackrest does not support changing the list of datasets after a repository
# is initialized YET. That's one feature I need.
included_datasets = ["storage/*"] # Glob is supported

[repository.s3]
# zfsbackrest does NOT support non-secure S3 endpoints.
endpoint = "todo"
bucket = "todo"
key = "todo"
secret = "todo"
region = "todo"

[repository.expiry]
# Child backups expire if the parent expires. See the model below for a better
# explanation.
full = "336h" # 14 days
diff = "120h" # 5 days
incr = "24h" # 1 day

[upload_concurrency]
full = 2
diff = 4
incr = 4

Creating a repository

$ zfsbackrest init --age-recipient-public-key="<your age public key>"

Backing up

$ zfsbackrest backup --type <full | diff | incr>

full backups are standalone. They do not depend on any other backups. They are also huge in size because of that.

diff backups are sent incrementally from the latest full backup. They depend on the parent full backup to be present in the repository to restore.

incr backups are send incrementally from the latest diff backup. They depend on the parent diff backup to restore.

Viewing the repository

$ zfsbackrest detail

It shows a list of backups, orphans and all.

Cleaning up the repository

Sometimes, orphaned backups are left as an artefact of incomplete or cancelled backups. You can clean those by running

$ zfsbackrest cleanup --orphans --dry-run=false

You can clean up expired backups by running

$ zfsbackrest cleanup --expired --dru-run=false

Restoring

To restore the backups, you'll need your age identity file (private key).

zfsbackrest restore -i <path-to-age-identity-file> \
  -s <name of the dataset to restore from> \
  -b <optionally, the backup ID to restore from, leave empty to restore the latest> \
  -d <name of the dataset to restore to> # Restoring to a dataset that already exists on your local FS will fail.

Safety

zfsbackrest doesn't write or modify actual zfs datasets. It makes extensive use of snapshots. List of zfs operations used by zfsbackrest are

• backup

  • zfs snapshot - Creating a zfs snapshot for zfsbackrest
  • zfs hold - Creating a reference to that snapshot to prevent removal
  • zfs send - Sending the snapshot incrementally

• cleanup / force-destroy

  • zfs release - Release the held snapshot
  • zfs destroy - Destroy the snapshot

• restore

  • zfs recv - Receiving the remote snapshot

Model

TODO