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Comment by Krisjohn | Hacker News Reader

btrfs is a horrible mess that will likely lose your data. For the few production systems we implemented it on, every single normal failure that other file systems can recover from had resulted in complete loss. We've had to implement a project to rebuild all systems that used btrfs in order to remove it.

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Ars Technica has acknowledged that stability has been achieved for single-disk filesystems. I've had no complaints, and the Fedora community has not reported major problems that I have heard.

"So, we'll repeat this once more: as a single-disk filesystem, btrfs has been stable and for the most part performant for years."

https://arstechnica.com/gadgets/2021/09/examining-btrfs-linu...

I dunno, I understand that the worst problems are in RAID, but it's only been a few years (<5y) since I lost 2 root filesystems to BTRFS on a laptop with just the one disk. I'm going to stay skeptical for a bit longer, although Fedora adopting it as a default does give me some hope that it'll at least get wider testing now.

I think fedora uses xfs by default not btrfs (at least in coreos version of f35)

https://fedoraproject.org/wiki/Btrfs#Default_filesystem,_on_... says they switched to BTRFS by default for the desktop edition with F33

They list the feature status here https://btrfs.wiki.kernel.org/index.php/Status It's not that raid has problems. Just one of the modes (raid5) is clearly documented as "unstable, don't use that".

It needs to be more than just avoiding tripping over itself, a real-world filesystem also needs to gracefully handle unclean poweroffs and such (and that's the kind of reliability I hope they will achieve..)

>btrfs is a horrible mess that will likely lose your data.

Meanwhile the bazillion petabytes on the world's synology NAS run fine, and are BTRFS.

Isn't synology running it hybridized with their own proprietary storage layer?

I believe it's a layer of mdadm and lvm rather than anything proprietary.

I could be wrong, but i think i remember that they have made some "magic" inside mdadm or lvm to allow btrfs self healing to work, and bypass the normal lvm self healing.

They tooted something around the release of DSM 7 that Btrfs now used native self healing instead of relying on lvm, but of course i can't find any documentation for it.

It's not proprietary, you can hook up the drives to a linux box and pull files off them just fine if your box dies. I've never had to do this, but I've seen others say they've done so successfully.

All of Facebook uses btrfs for their root filesystem (or did when I worked there). Millions of servers. They of course have the caveat of having kernel and btrfs developers working for them, and they run new kernels

they likely have huge replication infra on top of that which is resilient to individual partition problems.

I have been running btrfs at home with no losses. Mostly single, raid1 in a server. Array has been up ~4 years. While I doubt your comment that it will "likely lose your data", I am curious to know when (approximate kernel version/year) and how your losses occurred. There was clearly a history of data loss bugs, but it seems a little unfair to malign the system today after heaps of engineering went into stabilizing the filesystem.

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