ZFS Backup

Here’s a breakdown of the process:

Create a Snapshot

On the Source System (where you want to back up from):

zfs snapshot -r source_pool/dataset@backup_snapshot_name

This command creates a recursive snapshot (-r) of the source_pool/dataset and names it backup_snapshot_name. Replace source_pool/dataset with your actual ZFS dataset name and backup_snapshot_name with a descriptive name for your snapshot. 

Send the snapshot

(to a remote server via ssh from the Source System)

zfs send -R source_pool/dataset@backup_snapshot_name | ssh user@backup_server zfs recv -F backup_pool/backup_dataset

This command sends the snapshot stream to the remote server (backup_server) via ssh. 

• -R sends a replication stream, preserving all properties and descendent datasets.
• user is the username on the backup server.
• backup_server is the hostname or IP address of the backup server.
• backup_pool/backup_dataset is the ZFS dataset on the backup server where the data will be received.
• -F forces the receive, allowing it to overwrite existing data if needed.

Important Considerations:

• Encryption: For secure backups, especially over a network, consider using SSH with encryption or encrypting the ZFS pool itself on the backup server.
• Incremental Backups: For subsequent backups, you can send incremental snapshots using zfs send -i or zfs send -I. This significantly reduces transfer time and storage space.
• ZFS Versions: Ensure both the source and backup systems are running compatible ZFS versions.
• Space Requirements: ZFS snapshots can consume significant disk space. Regularly prune old snapshots to manage storage.
• Tools: Consider using tools like syncoid (part of the zfs-auto-snapshot package) or zfsnap for automating backups, snapshot management, and incremental transfers.
• Firewall: If using ssh, ensure that the firewall on the backup server allows incoming connections on the SSH port (usually 22).
• Network Bandwidth: For large datasets, consider using compression or tools like mbuffer to manage network bandwidth during transfers.