FreeBSD: Home NAS, part 1 – configuring ZFS mirror (RAID1)

By | 12/23/2025
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I have an idea to set up a home NAS on FreeBSD.

For this purpose, I bought a Lenovo ThinkCentre M720s SFF – it’s quiet, compact, and offers the possibility to install 2 SATA III SSDs plus a separate M.2 slot for an NVMe SSD.

What is planned:

  • on NVMe SSD: UFS and FreeBSD
  • on SATA SSDs: ZFS with RAID1

While waiting for the drives to arrive, let’s test how it all works on a virtual machine.

We will be installing FreeBSD 14.3, although version 15 is already out, but it has some interesting changes that I’ll play with separately.

Of course, I could have gone with TrueNAS, which is based on FreeBSD – but I want “vanilla” FreeBSD to do everything manually.

Installing FreeBSD via SSH

We will perform the installation over SSH using bsdinstall – boot the system in LiveCD mode, enable SSH, and then proceed with the installation from a workstation laptop.

The virtual machine has three disks – mirroring the future ThinkCentre setup:

Select Live System:

Login as root:

Bring up the network:

# ifconfig em0 up
# dhclient em0

Configuring SSH on FreeBSD LiveCD

For SSH, we need to set a root password and make changes to /etc/ssh/sshd_config, but currently, this doesn’t work because the system is mounted as read-only:

Check the current partitions:

And apply a “dirty hack”:

  • mount a new tmpfs file system in RAM at /mnt
  • copy the contents of /etc from the LiveCD there
  • mount tmpfs over /etc (overlaying the read-only directory from the ISO)
  • copy the prepared files from /mnt back into the new /etc

Execute:

# mount -t tmpfs tmpfs /mnt
# cp -a /etc/* /mnt/
# mount -t tmpfs tmpfs /etc
# cp -a /mnt/* /etc/

The mount syntax for tmpfs is mount -t <fstype> <source> <mountpoint>. Since the source value is required, we specify tmpfs again.

Now, set the password with passwd and start sshd using onestart:

# passwd
# service sshd onestart

However, SSH will still deny access because root login is disabled by default:

$ ssh [email protected]
([email protected]) Password for root@:
([email protected]) Password for root@:
([email protected]) Password for root@:

Set PermitRootLogin yes in /etc/ssh/sshd_config and restart sshd:

# echo "PermitRootLogin yes" >> /etc/ssh/sshd_config
# service sshd onerestart

Now we can log in:

$ ssh [email protected]
([email protected]) Password for root@:
Last login: Sun Dec  7 12:19:25 2025
FreeBSD 14.3-RELEASE (GENERIC) releng/14.3-n271432-8c9ce319fef7

Welcome to FreeBSD!
...

root@:~ #

Installation with bsdinstall

Run bsdinstall:

# bsdinstall

Select the components to add to the system – ports is necessary, src is optional but definitely worth it for a real NAS:

Disk partitioning

We’ll do a minimal disk partition, so select Manual:

We will install the system on ada0, select it, and click Create:

Next, choose a partition scheme. It’s standard for 2025 – GPT:

Confirm the changes, and now we have a new partition table on the system drive ada0:

The freebsd-boot Partition

Now we need to create the partitions themselves.

Select ada0 again, click Create, and create a partition for freebsd-boot.

This is just for the virtual machine; on the actual ThinkCentre, we would use type efi with a size of about 200-500 MB.

For now, set:

  • Type: freebsd-boot
  • Size: 512K
  • Mountpoint: empty
  • Label: empty

Confirm and proceed to the next partition.

The freebsd-swap Partition

Click Create again to add Swap.

Given that on the ThinkCentre we will have:

  • 8 – 16 GB RAM
  • no sleep/hibernate
  • UFS and ZFS

2 gigabytes will be enough.

Set:

  • Type: freebsd-swap
  • Size: 2GB
  • Mountpoint: empty
  • Label: empty

Root Partition with UFS

The main system will be on UFS because it is very stable, doesn’t require much RAM, mounts quickly, is easy to recover, and lacks complex caching mechanisms (UPD: however, after getting to know ZFS and its capabilities better, I decided to use it for the system disk as well)

Set:

  • Type: freebsd-ufs
  • Size: 14GB
  • Mountpoint: /
  • Label: rootfs – just a name for us

We’ll configure the rest of the disks later; for now, select Finish and Commit:

Finishing Installation

Wait for the copying to complete:

Configure the network:

Select Timezone:

In System Configuration – select sshd, no mouse, enable ntpd and powerd:

System Hardening – considering this will be a home NAS, but I might open external access (even behind a firewall), it makes sense to tune the security a bit:

  • read_msgbuf: allow dmesg access for root only
  • proc_debug: allow ptrace for root only
  • random_pid: randomize PID numbers
  • clear_tmp: clear /tmp on reboot
  • secure_console: require root password for login from the physical console

Add a user:

Everything is ready – reboot the machine:

Creating a ZFS RAID

Log in as the regular user:

$ ssh [email protected]
...
FreeBSD 14.3-RELEASE (GENERIC) releng/14.3-n271432-8c9ce319fef7
Welcome to FreeBSD!
...
setevoy@test-nas-1:~ $

Install vim 🙂

# pkg install vim

Check our disks.

Using geom disk for physical device info, and gpart show to see partitions on the disks.

Check disks – there are three:

root@test-nas-1:/home/setevoy # geom disk list
Geom name: ada0
Providers:
1. Name: ada0
   Mediasize: 17179869184 (16G)
   Sectorsize: 512
   Mode: r2w2e3
   descr: VBOX HARDDISK
   ident: VB262b53f7-adc5cd2c
   rotationrate: unknown
   fwsectors: 63
   fwheads: 16

Geom name: ada1
Providers:
1. Name: ada1
   Mediasize: 17179869184 (16G)
   Sectorsize: 512
   Mode: r0w0e0
   descr: VBOX HARDDISK
   ident: VB059f9d08-4b0e1f56
   rotationrate: unknown
   fwsectors: 63
   fwheads: 16

Geom name: ada2
Providers:
1. Name: ada2
   Mediasize: 17179869184 (16G)
   Sectorsize: 512
   Mode: r0w0e0
   descr: VBOX HARDDISK
   ident: VB3941028c-3ea0d485
   rotationrate: unknown
   fwsectors: 63
   fwheads: 16

And with gpart – current ada0 where the system was installed:

root@test-nas-1:/home/setevoy # gpart show
=>      40  33554352  ada0  GPT  (16G)
        40      1024     1  freebsd-boot  (512K)
      1064   4194304     2  freebsd-swap  (2.0G)
   4195368  29359024     3  freebsd-ufs  (14G)

Disks ada1 and ada2 will be used for ZFS and its mirror (RAID1).

If there was anything on them – wipe it:

root@test-nas-1:/home/setevoy # gpart destroy -F ada1
gpart: arg0 'ada1': Invalid argument
root@test-nas-1:/home/setevoy # gpart destroy -F ada2
gpart: arg0 'ada2': Invalid argument

Since this is a VM and the disks are empty, “Invalid argument” is expected and fine.

Create GPT partition tables on ada1 and ada2:

root@test-nas-1:/home/setevoy # gpart create -s gpt ada1
ada1 created
root@test-nas-1:/home/setevoy # gpart create -s gpt ada2
ada2 created

Check:

root@test-nas-1:/home/setevoy # gpart show ada1
=>      40  33554352  ada1  GPT  (16G)
        40  33554352        - free -  (16G)

Create partitions for ZFS:

root@test-nas-1:/home/setevoy # gpart add -t freebsd-zfs ada1
ada1p1 added
root@test-nas-1:/home/setevoy # gpart add -t freebsd-zfs ada2
ada2p1 added

Check again:

root@test-nas-1:/home/setevoy # gpart show ada1
=>      40  33554352  ada1  GPT  (16G)
        40  33554352     1  freebsd-zfs  (16G)

Creating a ZFS mirror with zpool

The “magic” of ZFS is that everything works “out of the box” – you don’t need a separate LVM and its groups, and you don’t need mdadm for RAID.

For managing disks in ZFS, the main utility is zpool, and for managing data (datasets, file systems, snapshots), it’s zfs.

To combine one or more disks into a single logical storage, ZFS uses a pool – the equivalent of a volume group in Linux LVM.

Create the pool:

root@test-nas-1:/home/setevoy # zpool create tank mirror ada1p1 ada2p1

Here, tank is the pool name, mirror specifies that it will be RAID1, and we provide the list of partitions included in this pool.

Check:

root@test-nas-1:/home/setevoy # zpool status
  pool: tank
 state: ONLINE
config:

        NAME        STATE     READ WRITE CKSUM
        tank        ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            ada1p1  ONLINE       0     0     0
            ada2p1  ONLINE       0     0     0

errors: No known data errors

ZFS immediately mounts this pool at /tank:

root@test-nas-1:/home/setevoy # mount
/dev/ada0p3 on / (ufs, local, soft-updates, journaled soft-updates)
devfs on /dev (devfs)
tank on /tank (zfs, local, nfsv4acls)

Check partitions now:

root@test-nas-1:/home/setevoy # gpart show
=>      40  33554352  ada0  GPT  (16G)
        40      1024     1  freebsd-boot  (512K)
      1064   4194304     2  freebsd-swap  (2.0G)
   4195368  29359024     3  freebsd-ufs  (14G)

=>      40  33554352  ada1  GPT  (16G)
        40  33554352     1  freebsd-zfs  (16G)

=>      40  33554352  ada2  GPT  (16G)
        40  33554352     1  freebsd-zfs  (16G)

If we want to change the mountpoint – execute zfs set mountpoint:

root@test-nas-1:/home/setevoy # zfs set mountpoint=/data tank

And it immediately mounts to the new directory:

root@test-nas-1:/home/setevoy # mount
/dev/ada0p3 on / (ufs, local, soft-updates, journaled soft-updates)
devfs on /dev (devfs)
tank on /data (zfs, local, nfsv4acls)

Enable data compression – useful for a NAS, see Compression and Compressing ZFS File Systems.

lz4 is the current default option, let’s enable it:

root@test-nas-1:/home/setevoy # zfs set compression=lz4 tank

Since we installed the system on UFS, we need to add a few parameters to autostart for ZFS to work.

Configure the boot loader in /boot/loader.conf to load kernel modules:

zfs_load="YES"

Or, to avoid manual editing, use sysrc with the -f flag:

root@test-nas-1:/home/setevoy # sysrc -f /boot/loader.conf zfs_load="YES"

And add to /etc/rc.conf to start the zfsd daemon and mount the file systems:

root@test-nas-1:/home/setevoy # sysrc zfs_enable="YES"
zfs_enable: NO -> YES

Reboot and check:

root@test-nas-1:/home/setevoy # zpool status
  pool: tank
 state: ONLINE
config:

        NAME        STATE     READ WRITE CKSUM
        tank        ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            ada1p1  ONLINE       0     0     0
            ada2p1  ONLINE       0     0     0

Everything is in place.

Now you can proceed with further tuning – configuring separate datasets, snapshots, etc.

For a Web UI, you could try Seafile or FileBrowser.