Introduction
ZFS (Zettabyte File System) offers powerful built-in features for data protection and backup. This guide explores advanced ZFS backup strategies to ensure your data remains safe and easily recoverable in various scenarios.
1. ZFS Snapshot Management
1.1 Creating Snapshot Schedules
Implement a robust snapshot schedule:
# Create hourly snapshots, kept for a day
$ zfs set snapdir=visible zroot/data
$ zfs set com.sun:auto-snapshot:hourly=true zroot/data
$ zfs set com.sun:auto-snapshot:hourly-keep=24 zroot/data
# Create daily snapshots, kept for a month
$ zfs set com.sun:auto-snapshot:daily=true zroot/data
$ zfs set com.sun:auto-snapshot:daily-keep=31 zroot/data
1.2 Snapshot Pruning
Automatically remove old snapshots:
# Remove snapshots older than 30 days
$ zfSnap -d 30 zroot/data
Tip: Use tools like zfSnap or zfs-auto-snapshot to automate snapshot creation and management.
2. Advanced ZFS Send and Receive
2.1 Incremental Send/Receive
Efficiently transfer only changed data:
# Initial full send
$ zfs send zroot/data@initial | ssh backup@remote 'zfs receive backup/data'
# Subsequent incremental send
$ zfs send -i zroot/data@initial zroot/data@incremental | ssh backup@remote 'zfs receive backup/data'
2.2 Resumable Send/Receive
Use the -s flag for resumable transfers:
$ zfs send -s zroot/data@snapshot | ssh backup@remote 'zfs receive -s backup/data'
2.3 Compressed Send/Receive
Reduce network bandwidth usage:
$ zfs send zroot/data@snapshot | gzip | ssh backup@remote 'gunzip | zfs receive backup/data'
3. ZFS Replication
3.1 Setting Up ZFS Replication
Create a continuous replication stream:
# On the source system
$ zfs allow -u replicator send,snapshot zroot/data
$ zfs allow replicator create,mount,receive backup
# On the destination system
$ zfs create backup/data
$ zfs set readonly=on backup/data
# Start replication
$ zfs send -R zroot/data@initial | ssh replicator@destination 'zfs receive -F backup/data'
3.2 Automating Replication
Use a script with cron to automate replication:
#!/bin/sh
latest_snap=$(zfs list -H -t snapshot -o name -s creation | tail -1)
zfs send -R -I @previous $latest_snap | ssh backup@remote 'zfs receive -F backup/data'
zfs bookmark $latest_snap ${latest_snap%@*}@previous
4. ZFS Encryption for Backups
4.1 Creating Encrypted Datasets
Ensure your backups are encrypted:
$ zfs create -o encryption=on -o keyformat=passphrase backup/encrypted_data
4.2 Sending Encrypted Snapshots
Transfer encrypted data securely:
$ zfs send -w zroot/encrypted_data@snapshot | ssh backup@remote 'zfs receive backup/encrypted_data'
Warning: Always securely store encryption keys and passphrases. Loss of these will result in unrecoverable data.
5. ZFS Pool Scrubbing and Verification
5.1 Regular Scrubbing
Perform regular data integrity checks:
# Start a scrub
$ zpool scrub zroot
# Check scrub progress
$ zpool status zroot
5.2 Verifying Received Data
Ensure received data integrity:
$ zfs receive -n backup/data < received_snapshot.zfs
6. ZFS Backup Best Practices
- Implement the 3-2-1 backup strategy: 3 copies of data, on 2 different media, with 1 copy off-site.
- Regularly test your backups by performing test restores.
- Use ZFS features like deduplication and compression to optimize storage usage.
- Monitor ZFS pool health and act promptly on any warnings or errors.
- Document your ZFS backup and restore procedures thoroughly.