I really wanted to make this article short … but I failed miserably. At least I tried to organize it well so one may get back to it after ‘some’ reading because its not a short lecture. I wanted to title it Why FreeBSD? but when you type that into your favorite duck.com search engine there are so many similar articles. I wanted it to have distinguished and unique name so I used Latin word for ‘why‘ which is ‘quare‘.
What FreeBSD can offer you that other operating systems does not? From all of the operating systems I used I find FreeBSD to suck the least. This post is not here to convince you to use or try FreeBSD – this you will have to do by yourself. This article will show you why FreeBSD is valuable or better alternative to other operating systems and is definitely not dying.
This is the Table of Contents for this article.
- Base System
- ZFS Boot Environments
- Rescue
- Audio
- Jails
- FreeBSD Ports Infrastructure
- Updating/Building from Source
- Storage
- Init System
- Linux Binary Compatibility
- Simplicity
- Evolution Instead Rewriting
- Documentation
- Community
- Closing Thoughts
- External Discussions
Base System
When you install a Linux system its just a bunch of RPM or DEB packages. For example of you install CentOS 7.8 Minimal variant you end up with several hundred RPM packages installed. After a week or month many of these packages will get updates sometimes making this CentOS system unusable or even unbootable (recent GRUB Boothole problem for example). On the contrary FreeBSD comes with a Base System concept. This means that when you install FreeBSD you install a minimal system as a whole. No packages or subsystems to be separately updated. Just whole Base System. That means that /boot /bin /sbin /usr /etc /lib /libexec /rescue directories are untouchable by any packages. When you decide to install packages (or build them using FreeBSD Ports) they will all fall into the /usr/local prefix. That means /usr/local/etc for configuration. The /usr/local/bin and /usr/local/sbin directories for binaries. The /usr/local/lib and /usr/local/libexec for libraries and so on. The FreeBSD Base System kernel modules are kept in the same dir along with the kernel in the /boot/kernel directory. To make things tidy all kernel modules that are provided by packages go into the /boot/modules dir. Everything has its place and its separated.
That is separation between Base System binaries (at /bin /sbin /usr/bin /usr/sbin dirs) and Third Party Packages maintained by pkg(8) and are located at /usr/local/bin and /usr/local/sbin dirs. We all know differences between bin (user) and sbin (root) binaries but in FreeBSD there is also another more UFS related separation. When there was only UFS filesystem in the FreeBSD world the /bin and /sbin binaries were available at boot after the root (/) filesystem was mounted and yet before /usrย filesystem was mounted – this is historical (and still useful in the UFS setups) distinction dating to old UNIX days. In ZFS setups it does not matter as all files are on ZFS pool anyway.
The FreeBSD Base System separation also helps with another thing – if any package gets the ‘great’ idea to install new compiler named cc and override the default system compiler … or to add libraries/includes in such a way that makes it super hard to get back into a working system. If some random FreeBSD package would add libc.so to /usr/local/lib dir then you are covered and not prevented from running programs as usual because FreeBSD system binaries are linked to stuff in /usr/lib dir. This is why there is PATH variable on UNIX systems (and FreeBSD as well) to set which directories should be searched for binaries first. On FreeBSD by default its set search Base System binaries dirs first and then Third Party Packages later.
You can update (or not) the Base System separately from the installed packages with freebsd-update(8) command when using RELEASE or by recompiling with make buildworld and make installworld commands when using STABLE/CURRENT systems. When it comes to packages you can update them using the pkg(8) tool or portmaster when building from FreeBSD Ports tree under /usr/ports dir. That means that any packages updates will not touch your FreeBSD Base System at all. For example when you mess up (and I have done that in the beginning of my FreeBSD journey) the compiled ports and packages and you want to start over the only thing you have to do is remove /usr/local and /boot/modules and /var/db/pkg directories. That’s it. You are just reverted to your Base System and can start over. This is just not possible when using Linux system. Even with Gentoo that many concepts are based on FreeBSD ideas does not have Base System feature. This Base System also have additional feature. Because its separated from packages version no one stops you from running oldshool FreeBSD 9.0 from 2012 and install there latest Firefox 80 or LibreOffice 7.0. You can not install latest Firefox on Ubuntu from 2012 …
One may be ‘afraid’ that such Base System independent from installed packages would take more space but nothing far more from the truth. The fresh installed FreeBSD 12.1 system uses less then 1 GB of disk space and takes less then 75 MB of RAM with sshd(8) running. For the comparison fresh CentOS 7.8 install with ‘Minimal’ set chosen takes 1.1 GB of disk space and uses more then 100 MB RAM with sshd(8) running. Such CentOS system is really naked and really needs more packages to be usable while FreeBSD with its Base System is far more capable and powerful and comes along with builtin latest version of LLVM/CLANG compiler suite for example.
More on the Base System topic:
ZFS Boot Environments
I have talked about this many times and probably one time too less because Linux world still ignores this bless. Having ZFS Boot Environments its such a game changer that once you realize how powerful it is you will never want to use a system that does not support it. The idea is that you can snapshot a running system at any moment of time and then reboot into that moment (or snapshot) if something happened. Its perfect solution for upgrade or changes to the system. The FreeBSD systems are already well ‘protected’ from problems arising after updating the packages but ZFS Boot Environments takes this to a whole new level.
Like in the movie Groundhog Day (1993) with ZFS Boot Environments you will have limitless chances to get your shit toghether. Even the Base System updates and changes are protected by it. You can even transport that Boot Environment by using zfs send and zfs recv commands to other system … or propagate it on many systems. You can create Jails containers from it … or install new version of FreeBSD in the new Boot Environment and reboot into it while still having your older ‘production’ system untouched.
More on the ZFS Boot Environments topic:
Rescue
When you really mess up to the point that even Base System concept or ZFS Boot Environments feature did not stopped you from killing your FreeBSD installation then there is one more level of rescue … the Rescue subsystem.
You have about 150 statically linked binaries available at your disposal for the rescue mission of that FreeBSD installation. You probably think now that if its so many binaries then it probably takes a lot of space … nothing far more from the truth. Its actually one static binary with hardlinks … and it takes whooping 11 MB of disk space.
# ls -lh /rescue | head -5
total 1118446
-r-xr-xr-x 146 root wheel 11M 2020.02.19 21:10 [
-r-xr-xr-x 146 root wheel 11M 2020.02.19 21:10 bectl
-r-xr-xr-x 146 root wheel 11M 2020.02.19 21:10 bsdlabel
-r-xr-xr-x 146 root wheel 11M 2020.02.19 21:10 bunzip2
They Rescue subsystem even contains such binaries as bectl(8) for ZFS Boot Environments management or zfs(8) and zpool(8) commands for the ZFS filesystem. Here is complete list of these binaries.
# ls /rescue
[ dd fsck_ffs init mdmfs ping rtsol unlink
bectl devfs fsck_msdosfs ipf mkdir ping6 savecore unlzma
bsdlabel df fsck_ufs iscsictl mknod pkill sed unxz
bunzip2 dhclient fsdb iscsid more poweroff setfacl unzstd
bzcat dhclient-script fsirand kenv mount ps sh vi
bzip2 disklabel gbde kill mount_cd9660 pwd shutdown whoami
camcontrol dmesg geom kldconfig mount_msdosfs rcorder sleep xz
cat dump getfacl kldload mount_nfs rdump spppcontrol xzcat
ccdconfig dumpfs glabel kldstat mount_nullfs realpath stty zcat
chflags dumpon gpart kldunload mount_udf reboot swapon zdb
chgrp echo groups ldconfig mount_unionfs red sync zfs
chio ed gunzip less mt rescue sysctl zpool
chmod ex gzcat link mv restore tail zstd
chown expr gzip ln nc rm tar zstdcat
chroot fastboot halt ls newfs rmdir tcsh zstdmt
clri fasthalt head lzcat newfs_msdos route tee
cp fdisk hostname lzma nextboot routed test
csh fsck id md5 nos-tun rrestore tunefs
date fsck_4.2bsd ifconfig mdconfig pgrep rtquery umount
More on the Rescue topic:
Audio
Not many people expect from FreeBSD to shine in that department but it shines a lot here and not from yesterday but from decades. Remember when Linux got rid of the old OSS subsystem with one channel and came up with ‘great’ idea to write ALSA? I remember because I used Linux back then. Disaster is very polite word to describe Linux audio stack back then … and then PulseAudio came and whole Linux audio system got much worse. Back then because of that one OSS channel and many ALSA channels meant that ONLY ONE application with OSS backend could do the sound (for example WINE). But if another application would want to ‘make’ sound using OSS and you already have WINE started then it will be soundless because that one and only OSS channel was already taken. And remember that ALSA was so bad back then that KDE or GNOME made their own sound daemons mixing audio in userspace that were incompatible with each other. That means if you used KDE and GNOME apps back then you could have sound from GNOME apps but not from KDE apps or vice versa. One big fucking audio hell on Linux.
Lets get back to FreeBSD audio then. What FreeBSD offered? A whooping 256 OSS channels mixed live in kernel for low latency. Everything audio related just worked out of the box – and still works today. You could have WINE or KDE/GNOME sound backends attached to their OSS channels and also ALSA apps getting their sound device without a problem. Even when you plugged a 5.1 surround system into FreeBSD it worked out of the box without any configuration and applications were able to use it immediately. That FreeBSD audio supremacy remains today as PulseAudio sound mixing in userspace while generally working incorporates large latency on Liunx compared to in kernel FreeBSD mixing with low latency.
Comrade meka suggested that FreeBSD is also the only OS which has virtual_oss that allows mixing/resampling/compressing in user space and allows one to have Bluetooth headphones and USB microphone represented as single sound card.
More on the Audio topic:
Jails
The FreeBSD Jails are one of the oldest OS Level Virtualization implementations dating back to 1999. Even the Solaris Zones/Containers came five years later in 2004.
After Docker was introduced in Linux the term OS Level Virtualization became less used to the Containers term and now the FreeBSD Jails along with Solaris Zones/Containers are named 1st generation containers. But that naming nomenclature change does not make FreeBSD Jails less powerful. They are also really brain dead simple to use. You just need a directory – for example /jail/nextcloud – where you will extract the FreeBSD Base System for desired release version – for example base.txz from 12.1-RELEASE and create the Jail config in the /etc/jail.conf file as shown below.
# mkdir -p /jail/nextcloud
# fetch -o - http://ftp.freebsd.org/pub/FreeBSD/releases/amd64/12.1-RELEASE/base.txz | tar --unlink -xpJf - -C /jail/nextcloud
# cat /etc/jail.conf
nextcloud {
host.hostname = nextcloud.local;
ip4.addr = 10.0.0.100;
path = /jail/nextcloud;
}
Now you can start you Jail right away.
# service jail onestart nextcloud
Starting jails: nextcloud.
Voila! Your FreeBSD Jail is already running.
# jls
JID IP Address Hostname Path
1 10.0.0.100 nextcloud.local /jail/nextcloud
You can of course have a trimmed down version of FreeBSD Base System in the Jail if that is needed. The ZFS filesystem also helps here greatly because with zfs clone only your ‘base’ Jail will take space and only the changes you make to Jails created from it. Thanks to other FreeBSD subsystem – the Linux Binary Compatibility – you can also create a Linux Jail – for example running Devuan Jail.
The FreeBSD Jails are also very lightweight. You can boot and use about 1000 FreeBSD Jails on a single FreeBSD system with 4 GB RAM.
They are also very easy to debug and troubleshoot comparing even to plain Docker – not to even mention Kubernetes which requires whole team of highly skilled people to maintain.
The FreeBSD Jails may be configured/managed only by the Base System utilities such as jls(8)/jexec(8) but you can also select from many third party Jail management frameworks. From all available ones I would choose BastilleBSD because of their modern approach and many ready to use templates for all needed use cases.
More on the Jails topic:
FreeBSD Ports Infrastructure
This is one of another examples why FreeBSD rocks that much. When you install Ubuntu or CentOS in some version there is chance that you will end up with not latest versions of packages but with versions that were quite up-to-date when this distribution version was released. Its especially visible in the CentOS world (and its upstream enterprise source system from Red Hat) where packages are quite up-to-date when .0 (dot zero) release is published but are VERY outdated when .8 or .9 incarnation of that release is available. Not to even mention that Firefox for example is released every month …
As I said before when describing the FreeBSD Base System the FreeBSD Ports (and packages built from it available through pkg(8)) are independent. That means that third party software from FreeBSD Ports is almost always up-to-date (or very close to it). You can even check it on the repology.org site for the details. Below you will find a ‘snapshot’ of the repology.org stats from time of writing this article. The ‘online’ table is very long so I copy/pasted just the systems relevant to the article.
One of the other advantages of FreeBSD Ports is that it offers really MASSIVE amount of software counting 40354 ports when writing this article and still rising. Amount of ready to be installed packages are little smaller with more then 32000 available.
I once migrated for a while to OpenSolaris in 2009 on my Dell Latitude D630 laptop because I really liked all the Solaris features (including ZFS and ZFS Boot Environments that were not available on FreeBSD back then) and the OpenSolaris GNOME based desktop was pretty nice back then even with Time Slider feature for ZFS snapshots in the Nautilus file manager. I got working WiFi connection, sound was working, generally everything on my laptop was supported and working with OpenSolaris … but there was no software. Of course ‘large’ projects like GIMP or OpenOffice was available even in the default pkg(8) repository but not much else. There was less then 4000 packages back then on OpenSolaris while about 25000 packages on FreeBSD if I recall correctly.
You can also easily browse available FreeBSD Ports (and its options) on the web by using the https://freshports.org/ page.
The count of FreeBSD Ports is one thing, the features is another. No matter which Linux distribution you are using you will find a software that was compiled and shipped without that needed flag that you desperately need. If you find such software on FreeBSD it ‘hurts’ only for a moment because you can VERY EASILY recompile that software with needed options and replace that ‘default’ package with yours. For example the FreeBSD project is afraid to provide packages of Lame because of existing MP3 patents, so multimedia/ffmpeg package is built without MP3 support (with --disable-libmp3lame flag). That is why I have my own audio/lame and multimedia/ffmpeg packages built with my configure options and that is very easy to achieve. You need to go to the /usr/ports/multimedia/ffmpeg dir type make config and select [x] LAME at the ncurses dialog. Your chosen options will be saved as plain /var/db/ports/multimedia_ffmpeg/options file. If you remove that file (or type make rmconfig) then these custom options will reset to defaults. Then you type make build deinstall install clean and your port with new options is ready and installed as package. Nothing more is needed. You can even lock that package from the pkg(8) upgrades with pkg lock -y ffmpeg command so it will not be modified later but its better to rebuild such packages everytime you do a pkg upgrade procedure because of libraries versions bump and changes. While its very easy and fast to create a script with these commands to make it more automated you can also use other parts of the FreeBSD Ports infrastructure – enter Poudriere (or Synth) – more on that in the next part.
You also do not have to configure each port that way (which could be PITA for large amount of ports) but you may specify your needed (OPTIONS_SET) or unwanted (OPTIONS_UNSET) parameters only once globally using the /etc/make.conf file. You can also specify which default versions of software you want to use, for example Apache 2.2 instead of 2.4 and PHP 7.0 instead of 7.2. You can find all default versions in the /usr/ports/Mk/bsd.default-versions.mk file. Once you setup these options you can build/rebuild or update your packages from FreeBSD Ports by portmaster(8) tool. Like on Gentoo Linux with USE flags. But this is the original. Gentoo took all/most of its ideas from FreeBSD system and its Ports infrastructure.
The Poudriere is a build framework that uses FreeBSD Ports and FreeBSD Jails to build requested packages in clean reproducible way. You can create whole new binary package repository for pkg(8) command to use with it. I mentioned Synth because while Poudriere is often used to produce whole package repository the Synth is usually used just to rebuild several packages that does not fit your needs.
There is one important things about FreeBSD Ports that is often misunderstood by newcomers. What is the difference between the Ports and packages that are fetched and installed by pkg(8) tool? Its quite simple. A package is just a build and installed port. Nothing more or less. When you use the binary packages using pkg(8) command you are using packages that someone (the FreeBSD project in that case) built for you from the FreeBSD Ports in some point in time. While FreeBSD strives to maintain as up-to-date built packages as possible its the nature of FreeBSD Ports that they are always more up-to-date then the built packages. That is why you may build and install a new version of needed packages by yourself using FreeBSD Ports. One may think of such usage when it comes to security holes. When some locally executed commands (like file(1) for example) has a security hole then its not critical for you to update it as fast as possible because that security hole can be harmless for you, but when new version of Firefox fixes very important security hole then its better to update from FreeBSD Ports version faster because waiting 2 days for the package to be built (along with other packages) can be too long.
More on the FreeBSD Ports topic:
Updating/Building from Source
While the FreeBSD Ports infrastructure is for third party software the FreeBSD Base System (or its parts) also can be easily and convenient build from source. The FreeBSD kernel config is also very small and simple. While Linux kernel config contains thousands of options – 4432 for example in the default CentOS 8.2 install the FreeBSD GENERIC config has about 20 times options less – only 260 options. But that does not saturate the topic. You can start with MINIMAL FreeBSD kernel config which has only 75 options specified.
Linux # grep -c '^CONFIG' /boot/config-$( uname -r )
4432
FreeBSD # grep -c -E '^(device|options)' /usr/src/sys/amd64/conf/GENERIC
260
FreeBSD # grep -c -E '^(device|options)' /usr/src/sys/amd64/conf/MINIMAL
75
… and its not only about smaller amount of options. Can you tell my how many steps (and which ones are required) to rebuild CentOS or Ubuntu for example without Bluetooth support?
On the contrary its very simple (and fast) on the FreeBSD side. While /etc/make.conf file is used to enable/disable Ports options the /etc/src.conf file is used to enable/disable FreeBSD Base System options while building it from source. To build FreeBSD without Bluetooth support just add WITHOUT_BLUETOOTH=yes to the /etc/src.conf file and type these to build it:
# beadm create safe
# cd /usr/src
# make buildworld kernel
# reboot
# cd /usr/src
# make installworld
# mergemaster -iU
# reboot
Voila! You now have FreeBSD without Bluetooth support … and if any of the steps failed or because of your lack of experience/expertise your FreeBSD system does not boot or is broken you can use tools from /rescue to try to fix it (or at least figure out what is broken) and when you do not want to cope with this jest select safe ZFS Boot Environment at the FreeBSD loader(8) to boot to the system before you started building modified version of FreeBSD. Yes, You are bulletproof here. While having 294 WITHOUT_X options and 125 WITH_X options you can really tune FreeBSD Base System to your needs.
# zgrep -c WITHOUT_ /usr/share/man/man5/src.conf.5.gz
294
# zgrep -c WITH_ /usr/share/man/man5/src.conf.5.gz
125
The big downside of updating FreeBSD by source is that you can not use the freebsd-update tools to do it … but nothing stops you from creating your own FreeBSD Update Server so you will be able to use freebsd-update by adding updates using a CURRENT or STABLE system instead of RELEASE. That process is described in the Build Your Own FreeBSD Update Server article of official FreeBSD documentation.
More on the FreeBSD Source Updates/Builds topic:
Storage
Storage is one of the parts where FreeBSD really shines. Lots of people adore FreeBSD for well integrated ZFS filesystem and its really true. ZFS in FreeBSD has always been first class citizen. Lately OpenZFS 2.0 has been also integrated from the upstream joint FreeBSD and Linux repository. More and more FreeBSD features and solutions are using ZFS features.
Most of these people that like integrated ZFS in FreeBSD do not know about the FreeBSD GEOM modular disk transformation framework which provides various storage related features and utilities like software RAID0/RAID1/RAID10/RAID3/RAID5 configurations or transparent encryption of underlying devices with GELI/GDBE (like LUKS on Linux). It also allows transparent filesystem journaling for ANY filesystem with GJOURNAL (yes also for FAT32 or exFAT) or allows one to export block devices over network with GEOM GATE devices (like NFS for block devices).
FreeBSD also has its own FUSE implementation which allows all these FUSE based filesystems to work natively on FreeBSD. While lots of Linux folks know DRBD probably very few of them knew that FreeBSD comes with its own DRBD like solution called HAST – which does exactly the same thing. While ZFS has a lot features and possibilities FreeBSD still maintains and develops fast and small memory footprint UFS filesystem which today is used either with Soft Updates (SU) or Journaled Soft Updates (SUJ) depending on the use case. For example 10 TB data on UFS filesystem with Journaled Soft Updates (SUJ) takes about 1 minute under fsck(8). These storage solutions are available from FreeBSD Base System alone. The FreeBSD Ports offers much more with distributed filesystems solutions such as CEPH, LeoFS, LizardFS or Minio for Amazon S3 compatible storage.
More on the Storage topic:
Init System
FreeBSD offers really simple yet very powerful init system. It has system wide config under /etc/rc.conf file when you can enable/disable needed services with service_enable=YES and service_enable=NO stanzas. You do not even need to launch vi(1) to add them – just type sysrc service_enable=YES and they are added to the /etc/rc.conf file. There are also default values and services that are enabled and you will find them – along with many comments – in the /etc/defaults/rc.conf file. Each FreeBSD service file has PROVIDE/REQUIRE stanzas which are then used to automatically order the services to start. Services that can be run in parallel are started in parallel to save time. For example its pointless to start sshd(8) daemon without network. To start or stop the serivice you need to type service sshd start or service sshd stop command. But when a service is not enabled in the /etc/rc.conf file then you need to used add onestart and onestop instead. The Base System separation remains here as FreeBSD Base System services are located at /etc/rc.d directory and third party applications from ports/packages are kept under /usr/local prefix which means /usr/local/etc/rc.d dir.
When using systemd(1) you never know how the services gonna start because it will be different each time. Zero determinism. On FreeBSD you know exactly which services will start when because they are always ordered in the same state according to the PROVIDE/REQUIRE stanzas. FreeBSD also offers tools that will tell you the exact order – rcorder(8) – which can be used for all services, Base System services or third party services separately. There is also service -r command that will show you what was the orfer at the boot time.
# rcorder /etc/rc.d/* | head
/etc/rc.d/growfs
/etc/rc.d/sysctl
/etc/rc.d/hostid
/etc/rc.d/zvol
/etc/rc.d/dumpon
/etc/rc.d/ddb
/etc/rc.d/geli
/etc/rc.d/gbde
/etc/rc.d/ccd
/etc/rc.d/swap
# rcorder /usr/local/etc/rc.d/* | tail
/usr/local/etc/rc.d/hald
/usr/local/etc/rc.d/git_daemon
/usr/local/etc/rc.d/fscd
/usr/local/etc/rc.d/cupsd
/usr/local/etc/rc.d/cups_browsed
/usr/local/etc/rc.d/clamav-clamd
/usr/local/etc/rc.d/clamav-milter
/usr/local/etc/rc.d/clamav-freshclam
/usr/local/etc/rc.d/avahi-dnsconfd
/usr/local/etc/rc.d/aria2
# rcorder /etc/rc.d/* /usr/local/etc/rc.d/* 2> | grep -C 3 sshd
/etc/rc.d/ubthidhci
/etc/rc.d/syscons
/etc/rc.d/swaplate
/etc/rc.d/sshd
/etc/rc.d/cron
/etc/rc.d/jail
/etc/rc.d/localpkg
Adding new service to FreeBSD is also very easy as template for new service is very small and simple.
#!/bin/sh
. /etc/rc.subr
name=dummy
rcvar=dummy_enable
start_cmd="${name}_start"
stop_cmd=":"
load_rc_config $name
: ${dummy_enable:=no}
: ${dummy_msg="Nothing started."}
dummy_start()
{
echo "$dummy_msg"
}
run_rc_command "$1"
If its not simple enought for you there is dedicated FreeBSD article about writing them – Practical rc.d Scripting in BSD – available here.
More on the Init System topic:
Linux Binary Compatibility
While Linux can not be FreeBSD – the FreeBSD can be Linux – and its not some slow emulation – its implementation of Linux system calls. There was time when enterprises used to work with Linux only applications (not available on FreeBSD by then) using the Linux Binary Compatibility on FreeBSD because it was faster then running them natively on Linux – FreeBSD Used to Generate Spectacular Special Effects – an official FreeBSD Press Release about FreeBSD being used to generate spacial effects to the one of the best movies of all time – The Matrix (1999).
Today the LINUX_COMPAT is also natively fast and allows one to run Linux applications – even Linux games in X11 with hardware acceleration for graphics. Think of it as WINE but for Linux applications. It lives under /compat/linux directory. It even implements Linux /proc virtual filesystem which can be mounted at the /compat/linux/proc dir but its not mandatory. For any software that does not come with source code and works on Linux the Linux Binary Compatibility saves the day. For example the f.lux project. Before I got to know Redshift I used f.lux Linux binary using LINUX_COMPAT to suppress blue spectrum light from my FreeBSD screen. The Linux Binary Compatibility subsystem can also be used to run Linux bases FreeBSD Jails – with Devuan for example.
More on the Linux Binary Compatibility topic:
Simplicity
FreeBSD is simple but not coarse/ornery. For example as Linux the FreeBSD system also supports the /proc virtual filesystem but on FreeBSD its optional and not used by default while Linux could not live without it. But while Linux has mandatory /proc it also has another virtual filesystem residing under /sys … but why Linux people need two different virtual filesystems with similar purposes? Why they could not create everything under /proc as it already existed. That is big enigma for my sanity.
But /sys is not the end of that madness. Its just a beginning.
What about these?
- securityfs
- devpts
- cgroup
- pstore
- bpf
- configfs
- selinuxfs
- systemd-1
- mqueue
- debugfs
- hugetlbfs
Take a look at the FreeBSD mount(8) output after the default install on ZFS.
FreeBSD # mount
zroot/ROOT/12.1 on / (zfs, local, noatime, nfsv4acls)
devfs on /dev (devfs, local, multilabel)
zroot/tmp on /tmp (zfs, local, noatime, nosuid, nfsv4acls)
zroot/var/mail on /var/mail (zfs, local, nfsv4acls)
zroot/usr/home on /usr/home (zfs, local, noatime, nfsv4acls)
zroot/var/crash on /var/crash (zfs, local, noatime, noexec, nosuid, nfsv4acls)
zroot/var/log on /var/log (zfs, local, noatime, noexec, nosuid, nfsv4acls)
zroot/var/audit on /var/audit (zfs, local, noatime, noexec, nosuid, nfsv4acls)
zroot/var/tmp on /var/tmp (zfs, local, noatime, nosuid, nfsv4acls)
zroot/usr/src on /usr/src (zfs, local, noatime, nfsv4acls)
zroot/usr/ports on /usr/ports (zfs, local, noatime, nosuid, nfsv4acls)
Several ZFS datasets and one virtual devfs filesystem for /dev directory. With install on UFS it would be similar with several UFS partitions mounted instead of ZFS datasets.
Take a look at the CentOS 8.2 installation with just one physical root (/) XFS filesystem.
[root@centos8 ~]# mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime,seclabel)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
devtmpfs on /dev type devtmpfs (rw,nosuid,seclabel,size=919388k,nr_inodes=229847,mode=755)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,seclabel)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,seclabel,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,seclabel,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,seclabel,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime,seclabel)
bpf on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,cpuset)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,memory)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,blkio)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,hugetlb)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,net_cls,net_prio)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,cpu,cpuacct)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,freezer)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,perf_event)
cgroup on /sys/fs/cgroup/rdma type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,rdma)
cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,pids)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,seclabel,devices)
configfs on /sys/kernel/config type configfs (rw,relatime)
/dev/sda1 on / type xfs (rw,relatime,seclabel,attr2,inode64,noquota)
selinuxfs on /sys/fs/selinux type selinuxfs (rw,relatime)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=34,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=17309)
mqueue on /dev/mqueue type mqueue (rw,relatime,seclabel)
debugfs on /sys/kernel/debug type debugfs (rw,relatime,seclabel)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,seclabel,pagesize=2M)
tmpfs on /run/user/0 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=187088k,mode=700)
Fuck me. Its even really hard to just find any REAL filesystem there … fortunately we can ask for only XFS filesystems to display.
[root@centos8 ~]# mount -t xfs
/dev/sda1 on / type xfs (rw,relatime,seclabel,attr2,inode64,noquota)
Lets get on the networking now. Lets assume that you want to make standard enterprise networking setup on a physical server with two interfaces aggregated together into highly available interface bond0 (lagg0 on FreeBSD) and then you want to put VLAN tag and IP address on that VLAN. The CentOS 7.x/8.x installer (Anaconda) will welcome you with this mess.
[root@centos7 ~]# ls -1 /etc/sysconfig/network-scripts/ifcfg-*
ifcfg-Bond_connection_1
ifcfg-eno49
ifcfg-eno49-1
ifcfg-eno50
ifcfg-eno50-1
ifcfg-VLAN_connection_1
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-Bond_connection_1
DEVICE=bond0
BONDING_OPTS="miimon=1 updelay=0 downdelay=0 mode=active-backup"
TYPE=Bond
BONDING_MASTER=yes
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_PRIVACY=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME="Bond connection 1"
UUID=ca85417f-8852-43bf-96ee-5bd3f0f83648
ONBOOT=yes
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno49
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eno49
UUID=2f60f50b-38ad-492a-b90a-ba736acf6792
DEVICE=eno49
ONBOOT=no
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno49-1
HWADDR=xx:xx:xx:xx:xx:xx
TYPE=Ethernet
NAME=eno49
UUID=342b8494-126d-4f3a-b749-694c8c922aa1
DEVICE=eno49
ONBOOT=yes
MASTER=bond0
SLAVE=yes
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno50
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eno50
UUID=4fd36e24-1c6d-4a65-a316-7a14e9a92965
DEVICE=eno50
ONBOOT=no
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno50-1
HWADDR=xx:xx:xx:xx:xx:xx
TYPE=Ethernet
NAME=eno50
UUID=a429b697-73c2-404d-9379-472cb3c35e06
DEVICE=eno50
ONBOOT=yes
MASTER=bond0
SLAVE=yes
[root@centos7 ~]# cat/etc/sysconfig/network-scripts/ifcfg-VLAN_connection_1
VLAN=yes
TYPE=Vlan
PHYSDEV=ca85417f-8852-43bf-96ee-5bd3f0f83648
VLAN_ID=601
REORDER_HDR=yes
GVRP=no
MVRP=no
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
IPADDR=10.20.30.40
PREFIX=24
GATEWAY=10.20.30.1
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_PRIVACY=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME="VLAN connection 1"
UUID=90f7a9bb-1443-4adf-a3eb-86a03b23ecfb
ONBOOT=yes
For the record – I have choosen ‘STATIC’ IPv4 address but installer made these interfaces to use DHCP and that STATIC address. That could be a bug but lets get to the point.
After manual fixing with vi(1) (and hour later) this is how it supposed to look.
[root@centos7 ~]# cat /etc/sysconfig/network
GATEWAY=10.20.30.1
NOZEROCONF=yes
[root@centos7 ~]# ls -1 /etc/sysconfig/network-scripts/ifcfg-*
ifcfg-bond0
ifcfg-bond0.601
ifcfg-eno49
ifcfg-eno50
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
BONDING_OPTS="miimon=1 updelay=0 downdelay=0 mode=active-backup"
TYPE=Bond
BONDING_MASTER=yes
BOOTPROTO=none
IPV4_FAILURE_FATAL=no
IPV6INIT=no
ONBOOT=yes
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-bond0.601
VLAN=yes
TYPE=Vlan
VLAN_ID=601
DEVICE=bond0.601
REORDER_HDR=yes
GVRP=no
MVRP=no
BOOTPROTO=none
IPADDR=10.20.30.40
PREFIX=24
IPV4_FAILURE_FATAL=no
IPV6INIT=no
ONBOOT=yes
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno49
BOOTPROTO=none
IPV4_FAILURE_FATAL=no
IPV6INIT=no
TYPE=Ethernet
NAME=eno49
DEVICE=eno49
ONBOOT=yes
MASTER=bond0
SLAVE=yes
[root@centos7 ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno50
BOOTPROTO=none
IPV4_FAILURE_FATAL=no
IPV6INIT=no
TYPE=Ethernet
NAME=eno50
DEVICE=eno50
ONBOOT=yes
MASTER=bond0
SLAVE=yes
Better … but still takes A LOT OF SPACE and several files to cover that quite simple setup. Not to mention its level of complication and making that very error prone way. The same configuration on FreeBSD would take just 7 lines within single /etc/rc.conf file as shown below.
ifconfig_fxp0="up"
ifconfig_fxp1="up"
cloned_interfaces="lagg0"
ifconfig_lagg0="laggproto failover laggport fxp0 laggport fxp1"
vlans_lagg0="601"
ifconfig_lagg0_601="inet 10.20.30.40/24"
defaultrouter="10.20.30.1"
What about the boot process? FreeBSD boots from root on ZFS partition with just small 512 KB not mountable partition. No separate /boot device is needed. On the other side Linux always needs that separate /boot partition filled with GRUB modules. No matter if its ZFS or LVM. That is why implementation of ZFS Boot Environments is quite complicated on Linux bacause even if you have root on ZFS on a Linux system there is still unprotected /boot filesystem that can not be snapshoted with ZFS and has to be protected in old classic way which kill the idea of ZFS Boot Environments or Linux.
FreeBSD is really simple and well thought operating system. But also a very underestimated one.
Evolution Instead Rewriting
How many Linux tools or subsystems are abandoned or superseeded by new ones? Why the ifconfig(8) command was not updated with new options and instead a new ip(8) command was introduced? Same with netstat(8) being replaced by ss(8). Same with arp(8)/iwconfig/route(8) and many more. What about whole init system? The Linux world has been taken over by systemd(1) whenever you like it or not. Even distributions that have grown their mature init systems like Ubuntu with its Upstart has moved to systemd(1) altogether. The distributions that do not use it are very few and considered a niche today.
In the FreeBSD land on the countary such things happen only if there is no other way to implement new things. Its the last thing wanted in the FreeBSD. FreeBSD evolves and is developed with stability and backward compatibility in mind. Userland tools are grown and updated with new options instead of rewriting them over and over again. Not to mention how many new bugs are introduced by changing one tool to another.
More on the Evolution Instead Rewriting topic:
Documentation
Having system that can do almost anything but not knowing how to do that makes that system pretty useless (or at least pretty PITA to use). FreeBSD offers second to none documentation that is actively maintained and updated. Along with its legendary FreeBSD Handbook and FreeBSD FAQ the FreeBSD project also offers official FreeBSD Articles about various FreeBSD topics. The Man Pages are also very detailed and contain many examples. There is also FreeBSD Wiki page for work in progress documentation and ideas related to FreeBSD development and if you have any problems or questions related to FreeBSD there are official FreeBSD Forums and oldschool Mailing Lists available.
These were only the official project knowledge sources but there are also lots of FreeBSD books. Here are the best and up-to-date ones.
- Absolute FreeBSD – Complete Guide to FreeBSD – 3nd Edition (2019)
- Beginning Modern Unix (2018)
- Book of PF – 3rd Edition (2015)
- Design and Implementation of FreeBSD 11 Operating System – 2nd Edition (2015)
- FreeBSD Device Drivers (2012)
- FreeBSD Mastery – ZFS (2015)
- FreeBSD Mastery – Advanced ZFS (2016)
- FreeBSD Mastery – Storage Essentials (2014)
- FreeBSD Mastery – Specialty Filesystems (2015)
- FreeBSD Mastery – Jails (2019)
There are also two magazines that are dedicated to BSD and FreeBSD systems. Both are free and cover lots of interesting topics regarding FreeBSD.
With all this knowledge and support its really hard not to achieve what you need/want with FreeBSD system.
Community
Last but not least and I would say its even more important then good documentation (which FreeBSD has awesome). People that use FreeBSD do that conciously and are often experienced not only in FreeBSD land but also in topics related to other UNIX systems. Often they took long road of first using the Linux systems before finally setting on the FreeBSD land or they still do Linux adminitration for a living while resting using far more reasonable and sensible FreeBSD solution. I always find FreeBSD Community helpful and friendly. Always willingly helpful – especially towards newcommers. Even when you try to ‘force’ FreeBSD people to ‘fight’ in unjust/doubtful discussion they will reply with dignity and technical arguments instead of yelling at you.
The FreeBSD project even made several articles and Handbook chapters especially for Linux newcommers (or sometimes called systemd(1) refugees).
Closing Thoughts
I tried really hard to not make it a Linux rant but some may feel it that way – if so please remember that this was not my intention. FreeBSD like Linux and like any other operating system has its ups and downs. Hope that I showed you most interesting FreeBSD parts. I may add new sections here without a warning in the future ๐
External Discussions
Discussions and comments from ‘external’ sources are available here:
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