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ZFS Basic Commands

Use at your own risk. All guides and scripts are provided for educational purposes only. Always review and understand any code before running it — especially with administrative privileges. Test in a safe environment before using in production. Your system, your responsibility.

A practical reference for the ZFS commands you will use most often. For initial setup see ZFS on Linux – Installation and Setup.

Pool Commands (zpool)

Command What it does
zpool list List all pools with size and usage
zpool status Detailed pool status and health
zpool status mypool Status of a specific pool
zpool iostat I/O statistics for all pools
zpool iostat mypool 2 Live I/O stats every 2 seconds
zpool scrub mypool Start a data integrity scrub
zpool history mypool Show command history for a pool
zpool export mypool Safely disconnect a pool
zpool import mypool Reconnect an exported pool
zpool destroy mypool Permanently delete a pool and all data

Dataset Commands (zfs)

Command What it does
zfs list List all datasets
zfs list -r mypool List all datasets in a pool
zfs create mypool/data Create a new dataset
zfs destroy mypool/data Delete a dataset
zfs rename mypool/data mypool/storage Rename a dataset
zfs get all mypool/data Show all properties of a dataset
zfs get used,avail mypool Show used and available space

Properties 

# Enable compression on a dataset
sudo zfs set compression=lz4 mypool/data

# Set a quota (max size a dataset can use)
sudo zfs set quota=500G mypool/data

# Set a reservation (guaranteed space)
sudo zfs set reservation=100G mypool/data

# Change mount point
sudo zfs set mountpoint=/mnt/data mypool/data

# Enable deduplication (use with caution — RAM intensive)
sudo zfs set dedup=on mypool/data

# Check compression ratio
zfs get compressratio mypool/data

Snapshots

Snapshots are instant, space-efficient point-in-time copies. They use no extra space until data changes.

# Create a snapshot
sudo zfs snapshot mypool/data@2026-03-27

# List all snapshots
zfs list -t snapshot

# List snapshots for a specific dataset
zfs list -t snapshot mypool/data

# Roll back to a snapshot (destroys changes made after the snapshot)
sudo zfs rollback mypool/data@2026-03-27

# Delete a snapshot
sudo zfs destroy mypool/data@2026-03-27

# Delete all snapshots older than a specific one
sudo zfs destroy mypool/data@2026-01-01%2026-03-01

Automated snapshots — install zfs-auto-snapshot for automatic scheduled snapshots:

sudo apt install -y zfs-auto-snapshot

This creates hourly, daily, weekly, and monthly snapshots automatically.

Clones

A clone is a writable copy of a snapshot — useful for testing without affecting production data:

# Create a clone from a snapshot
sudo zfs clone mypool/data@2026-03-27 mypool/data-test

# Delete the clone when done
sudo zfs destroy mypool/data-test

Sending and Receiving (Backup)

ZFS can send datasets to another pool or remote server — very efficient for backups:

# Send a snapshot to another pool (local)
sudo zfs send mypool/data@2026-03-27 | sudo zfs receive backuppool/data

# Send to a remote server via SSH
sudo zfs send mypool/data@2026-03-27 | ssh user@backup-server sudo zfs receive backuppool/data

# Incremental send (only changes since last snapshot — much faster)
sudo zfs send -i mypool/data@2026-03-20 mypool/data@2026-03-27 | \
  sudo zfs receive backuppool/data

Scrubs

A scrub reads all data in the pool and verifies checksums — detects and repairs corruption:

# Start a scrub
sudo zpool scrub mypool

# Check scrub progress
zpool status mypool

# Cancel a running scrub
sudo zpool scrub -s mypool

Run scrubs monthly on all your pools. It’s the best way to catch disk issues early.

Checking Pool Health 

zpool status

Look for the state field:

  • ONLINE — all good
  • DEGRADED — a disk has failed, pool still works but with reduced redundancy
  • FAULTED — serious problem, data may be at risk
  • OFFLINE — a disk is intentionally offline

If a disk fails:

# See which disk failed
zpool status mypool

# Replace the failed disk
sudo zpool replace mypool /dev/disk/by-id/OLD-DISK-ID /dev/disk/by-id/NEW-DISK-ID

# Watch the resilver (rebuild) progress
zpool status mypool

Quick Reference 

# Pool health
zpool status

# Space usage
zpool list
zfs list

# Create snapshot
zfs snapshot mypool/data@$(date +%Y-%m-%d)

# List snapshots
zfs list -t snapshot

# Start scrub
zpool scrub mypool

# Enable compression
zfs set compression=lz4 mypool

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