A brief history of OpenZFS and TrueNAS CORE®

Creation of ZFS

The Zettabyte Filesystem (ZFS) is a scalable file system and logical volume manager that was created in 2001 by Matthew Ahrens and Jeff Bonwick while working for Sun Microsystems to be used in their Solaris operating system. Its core goal was to overcome the limitations of existing filesystems, such as the ability to host a large number of files, the maximum storage capacity, the inability to span multiple disks without additional hardware, etc.

ZFS was designed to be a scalable filesystem with plenty of advanced features like:

• storage pooling
• extensive protection against data corruption
• support for high storage capacities
• support for file size of up to 16 Exabyte
• support for 256 Quadrillion Zettabytes pool size
• efficient in-line data compression
• copy-on-write and snapshots
• continuous integrity checking and automatic repair
• native NFSv4 ACLs
• RAID-Z which provides RAID-like abilities and complements the volume management capabilities of the filesystem.

Berth of OpenZFS and ZFS on Linux

Initially, ZFS was closed-source, but in 2005 Sun Microsystems opened the source of its Solaris OS (which included their ZFS code-base) under a GPL license and the OpenSolaris OS was born.  

A few years later Oracle bough Sun and closed the source again. But by that time the source code has already been open for a good while. Developers quickly forked OpenSolaris and the illumos OS was created to replace it. The ZFS portion of the code was successfully ported to multiple open-source Unix-based OS platforms such as FreeBSD and macOS.

In 2013 a group of developers initiated the OpenZFS project to help coordinate development efforts and avoid code fragmentation. Their initiative made ZFS widely available within Unix-like systems especially FreeBSD whose developers maintained the most stable and feature-rich branch of the code, which in turn lead to OpenZFS being referred to as ZFS on FreeBSD (ZoF).

Because they originated from the same code-base, both OpenZFS and the original ZFS are extremely similar. Due to this similarity, OpenZFS is usually referred to as ZFS. Also, the proprietary version of ZFS currently exists only in the Solaris OS. All other platforms are using OpenZFS or ZFS on Linux (ZoL), which is the Linux port of OpenZFS that was first released in 2013. This is also why, within open-source enthusiasts, both ZoF and ZoL are usually referred to as ZFS.

OpenZFS and ZFS on Linux merging

ZoF remained, for a good while, the leading open-source branch of ZFS. But the increasing popularity of Linux and its relatively larger user and developer base eventually lead to ZoL catching up with ZoF. ZoF developers, on the other hand were slower to import newer features into their release because they were focused on stability of the filesystem. This difference in development paces quickly lead to ZoL being the superior branch when it comes to feature-richness. In 2019 ZoL was available for use in many leading Linux distros and in mid 2020 Ubuntu – the most popular Linux distribution – released version 20.04 LTS with support for ZFS as the root filesystem for the OS.

In December 2020, and with the release of OpenZFS V2.0.0, the maintainers of ZoF announced they are merging with ZoL, ending years of distinction between ZoL and ZoF and everywhere else.

This was actually great news because by that time ZoL was the more advanced branch with plenty of features that ZoF was lacking such as Persistent L2ARC and Sequential Resilvering.

FreeNAS

The FreeNAS project was started in 2005 by iXsystems. It was initially based on a micro-distribution of Linux. In 2010 the developers decided to rebase their solution on FreeBSD to benefit from its stability and the more advanced ZFS code within.

In spite of all the cool features of ZFS, it was still quite challenging to use because it was 100% Commandline-based. This led to the majority of its users being either experienced Unix admins or tech savvy enthusiasts. Those with no Unix shell administration skills were left out. It was a very unfortunate situation.

The other negative thing was that ZFS was just a filesystem. To be able to connect a client to a ZFS server to store data on it you still needed to configure and enable some common sharing protocol, such as NFS or SMB, on that server to turn it into a Network Attached Storage (NAS). This was also quite challenging, especially with ZFS being adopted by the much less popular distributions, OpenSolaris and the likes. 

FreeNAS was created to bridge this gab and provide a stable ZFS open-source NAS-focused solution with a user-friendly Web GUI.  iXsystems used to produce two versions of their popular NAS solution with TrueNAS being the enterprise edition (paid for) and FreeNAS being the open-source (free) version. This meant that both versions used to have separate code-bases and also different installation ISO files.

TrueNAS CORE – Where did FreeNAS go?

In March 2020 iXsystems announced they will be consolidating both FreeNAS and TrueNAS into a single software image and name – TrueNAS.

There are two versions of TrueNAS:

• TrueNAS CORE: free to use with unrestricted feature-set and no capacity limit.
• TrueNAS Enterprise: requires a license to enable advanced features such as high-availability.

So, TrueNAS CORE is the new name for FreeNAS. It the same software that has been tried and tested by hundreds of thousands of users and has won the trust of many enterprise IT professionals. When properly configured, TrueNAS can provide a robust and secure storage backend to many applications, ranging between SOHO and multi-terabyte enterprise pools. With TrueNAS you get the latest iteration of OpenZFS which include the latest file-system features, updates and patches.

TrueNAS supports Windows, macOS and Unix clients and various virtualisation hosts such as XenServer and VMware using the SMB, AFP, NFS, iSCSI, SSH, rsync and FTP/TFTP protocols. Advanced TrueNAS features include full-disk encryption and a plug-in architecture for third-party software.