ZFS on FreeBSD

List disks

Using geom:

geom disk list

Or, install lsblk as you would on Linux:

sudo pkg install lsblk
lsblk

Create pool

Create a basic mirror pool:

zpool create tank mirror /dev/da0 /dev/da1

Create a striped-mirror pool (similar to raid-10):

zpool create tank mirror /dev/da0 /dev/da1 mirror /dev/da2 /dev/da3

Create dataset

/tank/backups

zfs create -o compress=lz4 tank/backups

Snapshots

Take a snapshot:

sudo zfs snapshot -r zroot@now

Take a snapshot, with an automatically generated name:

sudo zfs snapshot -r zroot@$(date "+%Y%m%d%H%M.%S")

List available snapshots:

zfs list -t snapshot

NAME               USED  AVAIL     REFER  MOUNTPOINT
zroot@2021-06-30     0B      -       96K  -

Delete a snapshot:

sudo zfs destroy zroot@2021-06-30

Compare a snapshot state:

zfs diff zroot/usr/home@202107011206.09
Password:
M   /usr/home/noah/.bash_history
+   /usr/home/noah/Desktop/1.txt
+   /usr/home/noah/Desktop/2.txt
+   /usr/home/noah/Desktop/3.txt
+   /usr/home/noah/Desktop/4.txt
M   /usr/home/noah/Desktop

Devices

List pools:

zpool list

NAME    SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
zroot  37.5G  3.23G  34.3G        -         -     1%     8%  1.00x    ONLINE  -

Check device health:

zpool status

pool: zroot
state: ONLINE
config:

    NAME           STATE     READ WRITE CKSUM
    zroot          ONLINE       0     0     0
    vtbd0p3.eli  ONLINE       0     0     0

errors: No known data errors

Scrubs

Perform a disk scrub

sudo zpool scrub zroot

Check scrub status:

zpool status


pool: zroot
state: ONLINE
scan: scrub in progress since Tue Jun 29 22:51:19 2021
    2.27G scanned at 232M/s, 260K issued at 26K/s, 3.23G total
    0B repaired, 0.01% done, no estimated completion time
config:

    NAME           STATE     READ WRITE CKSUM
    zroot          ONLINE       0     0     0
    vtbd0p3.eli  ONLINE       0     0     0

errors: No known data errors

Replication

Send a snapshot on the local system, to another array on the local system

zfs send -R -v zroot@202107011210.16 | zfs recv tank/zroot-backup

Send a differential backup based on yesterday's snapshot:

zfs send -R -v -i zroot@202107011210.16 zroot@202107022003.05 | zfs recv tank/zroot-backup

Automatic snapshot script

#!/bin/sh

NUM_SNAPSHOTS=`zfs list -t snapshot zroot | awk '/@/{print $1}' | wc -l`
echo "[+] ${NUM_SNAPSHOTS} snapshots on volume"

echo "[+] Getting last snapshot on system"
LAST_SNAPSHOT=`zfs list -t snapshot zroot | tail -n1 | awk '{print $1}'`

echo "[+] Taking system snapshot"
zfs snapshot -r zroot@$(date "+%Y%m%d-%H%M")
NEW_SNAPSHOT=`zfs list -t snapshot zroot | tail -n1 | awk '{print $1}'`

echo "[+] Sending incremental backup"
zfs send -R -v -i $LAST_SNAPSHOT $NEW_SNAPSHOT | zfs recv tank/zroot-backup

echo "[+] Deleting oldest snapshot"
OLDEST_SNAPSHOT=`zfs list -t snapshot zroot | awk '/@/{print $1}' | head -n1`
zfs destroy -r -v "${OLDEST_SNAPSHOT}"
echo "[+] Deleted snapshot $OLDEST_SNAPSHOT"