FreeBSD for newcomers

What you will learn

• How FreeBSD is organised, in just enough detail to use zfsctl comfortably.
• The few commands you will use every day: pkg, service, sysrc, geom and friends.
• How FreeBSD names disks.

FreeBSD is developed by the volunteers of the FreeBSD Project, and zfsctl exists because of their work; ZFS in FreeBSD comes from OpenZFS. If you already run FreeBSD, skim the headings and move on to Installing. For depth, the FreeBSD Handbook is excellent.

One system, not a distribution

FreeBSD is a complete operating system: kernel, libraries and basic tools come together from one project and are released together (the test hub in this book runs 15.1-RELEASE). Software you add yourself lives apart, under /usr/local: its programs in /usr/local/bin, its configuration in /usr/local/etc. The base system never touches /usr/local, and packages never touch the base. That is why zfsctl installs to /usr/local/bin/zfsctl and its configuration is /usr/local/etc/zfsctl/config.toml.

Installing software with pkg

pkg search restic        # find a package
pkg install restic       # install it (as root)
pkg info restic          # what is installed, and which version
pkg upgrade              # upgrade installed packages

On the test hub, pkg info shows restic-0.19.1, rclone-1.75.1 and msmtp-1.8.32: the three extra tools zfsctl can use for backups and mail (chapters 15 and 16).

Services: rc.conf, sysrc and service

FreeBSD starts services from small scripts in /etc/rc.d (base) and /usr/local/etc/rc.d (packages). Which ones start at boot is set in /etc/rc.conf, and you change that file with sysrc, which edits it safely:

sysrc zfsctl_enable=YES      # start zfsctl's daemon at boot
service zfsctl start         # start it now
service zfsctl status        # is it running?
sysrc zfsctl_enable          # what is the setting?

On the test hub, sysrc zfsctl_enable zfs_enable prints zfsctl_enable: YES and zfs_enable: YES, and ls /usr/local/etc/rc.d shows the zfsctl script. A service is "enabled" only when rc.conf says NAME_enable="YES".

Disks have driver names

FreeBSD names a disk after the driver that found it, plus a number. The most common:

The test hub's disks are ada0 (the system disk) and ada1 to ada4 (the disks of the tpool pool, 5 GB each). A name can change if you move a disk to another port, so zfsctl also shows each disk's model and serial number, which is how you tell which physical disk is which before you replace one.

geom disk list           # every disk with its size, model and serial
zpool status             # which disks are in which pool

Users, root and sudo

FreeBSD has a root account and the wheel group (the people allowed to become root). Installing sudo (pkg install sudo) works as on Linux, and doas is available as a package (security/doas). zfsctl itself must be started by root on the hub, and on every other host it uses an ordinary user that may run only a short list of commands through sudo (chapter 5).

A few more things you will meet

• kldload and kldstat load and list kernel modules (zfs.ko).
• freebsd-update fetch install updates the base system (FreeBSD 15 also offers the base as packages, pkgbase, which pkg then updates; see the release notes); bectl manages boot environments, which let you roll back an upgrade (chapter 13).
• man zfs, man zpool, man rc.conf: the manual pages are complete and worth reading.
• dmesg shows what the kernel found at boot, including your disks.

Jails

FreeBSD jails are lightweight containers built into the system, much like Linux containers or Docker, but older and simpler. They are common on ZFS machines because a jail's files can be a dataset you snapshot and replicate like any other.

A jail's datasets are ordinary datasets, so everything in this book works on them.

Try it

On any FreeBSD machine, as an ordinary user, run these read-only commands and look at what they tell you:

freebsd-version
geom disk list
zpool list
pkg info | head
service -e | head

Where next

• Installing to put zfsctl on your hub.
• ZFS in 15 minutes if you have not read it.