jd's Journal: OpenZFS 2.2 data corruption issue, high reliability alternatives

There is a rare but repeatable bug in all versions of OpenZFS that silently corrupts data. This includes the pre- releases. 2.2.1 seems to reduce the odds of it happening but does not fix the issue.

From the reports I'm seeing, it would appear that nobody actually understands how ZFS (or Btrfs, for that matter) actually works, they're limited to whatever component they've specialised in.

Linux has a kernel mechanism for improving data reliability on filing systems that support it - dm-integrity.

I've no idea how well tested this component is. I don't recall ever having heard of it before. A quick Google suggests that it works but is very slow, though I would inagine it will improve with time.

Phoronix, OpenZFS Data Corruption Battle
TRUENAS, Corruption with OpenZFS ongoing
YCombinator, OpenZFS silent corruption bug
Level 1 Techs, OpenZFS silent corruption bug

OpenZFS is not included in the Linux kernel by default dud to licensing issues, but I believe it is currently developed on Linux and ported to other OS'. (Wikipedia says that this has been the case since 2013.) It now runs in the kernel, so it's a lot faster than it was when it worked with Fuse.

Wikipedia, OpenZFS

This is a high performance, high reliability filing system, so data corruption is really bad news. It's designed for the enterprise and outclasses Microsoft's RefFS on essentially every stat. Irs main disadvantage is that it is resource-intensive, although the license is another important issue.

One drawback with OpenZFS is that it doesn't currently support RAID. Which is odd, given the intended market.

Interestingly, I don't know of any cloud providers or corporations that actually use OpenZFS. Ext4 tends to be more popular, at the expense of enterprise features.

Oracle has re-closed Solaris' ZFS, so the two filesystems are no longer compatible. But as effectively nobody uses Oracle Solaris, this doesn't matter much.

I guess the main takeaways with the current OpenZFS bug are that filing systems are becoming too complex for the hunt-and-peck approach often used in both commercial and open source projects, and that the popularity of other filing systems in OpenZFS' own domain suggests that feature-rich filesystems might actually be the wrong approach.