ZFS was introduced to FreeBSD in 2008 in FreeBSD 7.0, it was set to the "default" on supported systems three years ago. But I believe Alex Seitsinger was referring to ZFS as a technology, not to the length of time it had been the "default"...2020 is not exactly 15 years ago...
ZFS was designed as an enterprise filesystem, for people who research their requirements and plan accordingly. The biggest downfall I've seen (across FreeBSD, FreeNAS, and Linux) is that people do stuff (like setting up specific RAID layouts) without really thinking about what they want to do, and are then shocked when ZFS doesn't suddenly perform magic when they find out they didn't actually gather their requirements, plan, and execute.So it's not yet hassle-free, is it? That may have to do with the tools and docs too. I noticed that the terms used in ZFS are not always very comprehensible. For instance, the term 'resilver' in case of a new disk. Are we going to plate that thing with silver or is it about (re)initializing it? Same with 'scrub'. With water and a brush or is it just a file system check? Many terms are far from self-explanatory, hence users will have to read all the docs. They could have made things easier.
That being said, some of the biggest of these issues are being worked on, and it's improving all of the time.
It doesn't sound like you're using RAID of any kind from one of your other posts. But just be aware that disks are often not exactly the same size, so if in the future you try and mirror your ZFS disk and the new disk is slightly smaller you will be unable to mirror it. Usually it's recommended to make a single partition that's a few megabytes smaller than the disk to make 100% sure that you can add/replace a mirror at a later date.Letting ZFS take over the entire disk was the best decision I made...I already forgot everything I knew about disk partitioning, and I'm on cloud 9 from that!
I've not tried encryption yet, but have used snapshots (as well as things that rely on snapshots/snapshotting like Boot Environments, clones, send/receive), compression, raid, deduplication (a long time ago), quotas... The docs are good, when I need to do something I find the man pages pretty good, and the books by Michael Lucas are also great.Apart from snapshots, do you use other ZFS-features like compression, encryption and raid?
That all being said I learnt ZFS from people that worked on it in Solaris while I was at university, I count myself lucky to have learnt it so early from people that intimately knew it - it's just a shame I've used it mostly at home on account of working mainly in Linux shops that tend to mandate whatever the default file system in on whatever Linux distro we use.
As mer said, typically it is worth it. This article has some nice explanations on how compression works, and it's important to note that ZFS doesn't blindly try to compress everything.Apart from snapshots I would not be using most of these features. Compression allows for efficient use of disk space, which is a good thing. OTOH, it won't speed things up and in the long run the additional electricity cost of (de)compression may set you back more than a bigger disk just once. It all depends on your needs.
The article sets it up and explains it better than I could, but is ZFS can't get a good enough compression ration then data is stored in its original form and incurs no additional CPU overhead.