4. Installation of the FreeBSD Operating System

The mfsBSD has been successfully booted and it should be possible to log in through ssh(1). This section will describe how to create and label slices, set up gmirror for RAID-1, and how to use sysinstall to install a minimal distribution of the FreeBSD operating system.

4.1. Preparation of Hard Drives

The first task is to allocate disk space for FreeBSD, i.e.: to create slices and partitions. Obviously, the currently running system is fully loaded in system memory and therefore there will be no problems with manipulating hard drives. To complete this task, it is possible to use either sysinstall or fdisk(8) in conjunction to bsdlabel(8).

At the start, mark all system disks as empty. Repeat the following command for each hard drive:

# dd if=/dev/zero of=/dev/ad0 count=2

Next, create slices and label them with your preferred tool. While it is considered easier to use sysinstall, a powerful and also probably less buggy method will be to use standard text-based UNIX® tools, such as fdisk(8) and bsdlabel(8), which will also be covered in this section. The former option is well documented in the Installing FreeBSD chapter of the FreeBSD Handbook. As it was mentioned in the introduction, this article will present how to set up a system with RAID-1 and ZFS capabilities. Our set up will consist of a small gmirror(8) mirrored / (root), /usr and /var dataset, and the rest of the disk space will be allocated for a zpool(8) mirrored ZFS file system. Please note, that the ZFS file system will be configured after the FreeBSD operating system is successfully installed and booted.

The following example will describe how to create slices and labels, initialize gmirror(8) on each partition and how to create a UFS2 file system in each mirrored partition:

# fdisk -BI /dev/ad0 1
# fdisk -BI /dev/ad1
# bsdlabel -wB /dev/ad0s1 2
# bsdlabel -wB /dev/ad1s1
# bsdlabel -e /dev/ad0s1 3
# bsdlabel /dev/ad0s1 > /tmp/bsdlabel.txt && bsdlabel -R /dev/ad1s1 /tmp/bsdlabel.txt 4
# gmirror label root /dev/ad[01]s1a 5
# gmirror label var /dev/ad[01]s1d
# gmirror label usr /dev/ad[01]s1e
# gmirror label -F swap /dev/ad[01]s1b 6
# newfs /dev/mirror/root 7
# newfs /dev/mirror/var
# newfs /dev/mirror/usr


Create a slice covering the entire disk and initialize the boot code contained in sector 0 of the given disk. Repeat this command for all hard drives in the system.


Write a standard label for each disk including the bootstrap code.


Now, manually edit the label of the given disk. Refer to the bsdlabel(8) manual page in order to find out how to create partitions. Create partitions a for / (root) file system, b for swap, d for /var, e for /usr and finally f which will later be used for ZFS.


Import the recently created label for the second hard drive, so both hard drives will be labeled in the same way.


Initialize gmirror(8) on each partition.


Note that -F is used for the swap partition. This instructs gmirror(8) to assume that the device is in the consistent state after the power/system failure.


Create a UFS2 file system on each mirrored partition.

4.2. System Installation

This is the most important part. This section will describe how to actually install the minimal distribution of FreeBSD on the hard drives that we have prepared in the previous section. To accomplish this goal, all file systems need to be mounted so sysinstall may write the contents of FreeBSD to the hard drives:

# mount /dev/mirror/root /mnt
# mkdir /mnt/var /mnt/usr
# mount /dev/mirror/var /mnt/var
# mount /dev/mirror/usr /mnt/usr

When you are done, start sysinstall(8). Select the Custom installation from the main menu. Select Options and press Enter. With the help of arrow keys, move the cursor on the Install Root item, press Space and change it to /mnt. Press Enter to submit your changes and exit the Options menu by pressing q.


Note that this step is very important and if skipped, sysinstall will be unable to install FreeBSD.

Go to the Distributions menu, move the cursor with the arrow keys to Minimal, and check it by pressing Space. This article uses the Minimal distribution in order to save network traffic, because the system itself will be installed over ftp. Exit this menu by choosing Exit.


The Partition and Label menus will be skipped, as these are useless now.

In the Media menu, select FTP. Select the nearest mirror and let sysinstall assume that the network is already configured. You will be returned back to the Custom menu.

Finally, perform the system installation by selecting the last option, Commit. Exit sysinstall when it finishes the installation.

4.3. Post Installation Steps

The FreeBSD operating system should be installed now; however, the process is not finished yet. It is necessary to perform some post installation steps in order to allow FreeBSD to boot in the future and to be able to log in to the system.

You must now chroot(8) into the freshly installed system in order to finish the installation. Use the following command:

# chroot /mnt

To complete our goal, perform these steps:

  • Copy the GENERIC kernel to the /boot/kernel directory:

    # cp -Rp /boot/GENERIC/* /boot/kernel
  • Create the /etc/rc.conf, /etc/resolv.conf and /etc/fstab files. Do not forget to properly set the network information and to enable sshd in /etc/rc.conf. The contents of /etc/fstab will be similar to the following:

    # Device                Mountpoint      FStype  Options         Dump    Pass#
    /dev/mirror/swap        none            swap    sw              0       0
    /dev/mirror/root        /               ufs     rw              1       1
    /dev/mirror/usr         /usr            ufs     rw              2       2
    /dev/mirror/var         /var            ufs     rw              2       2
    /dev/cd0                /cdrom          cd9660  ro,noauto       0       0
  • Create /boot/loader.conf with the following contents:

  • Perform the following command, which will make ZFS available on the next boot:

    # echo 'zfs_enable="YES"' >> /etc/rc.conf 
  • Add additional users to the system using the adduser(8) tool. Do not forget to add a user to the wheel group so you may obtain root access after the reboot.

  • Double-check all your settings.

The system should now be ready for the next boot. Use the reboot(8) command to reboot your system.

All FreeBSD documents are available for download at https://download.freebsd.org/ftp/doc/

Questions that are not answered by the documentation may be sent to <freebsd-questions@FreeBSD.org>.
Send questions about this document to <freebsd-doc@FreeBSD.org>.