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Bcachefs Goes to "Externally Maintained"

(lwn.net)
214 points ksec | 5 comments | 30 Aug 25 13:07 UTC | HN request time: 0.646s | source
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LeoPanthera ◴[30 Aug 25 17:28 UTC] No.45076431[source]▶
It's orphaned in Debian as well, but I'm not sure what significant advantages it has over btrfs, which is very stable these days.
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betaby ◴[30 Aug 25 17:47 UTC] No.45076586[source]▶
btrfs was unusable in multi disk setup for kernels 6.1 and older. Didn't try since then. How's stable btrs today in such setups?

Also see https://www.phoronix.com/news/Josef-Bacik-Leaves-Meta

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LeoPanthera ◴[30 Aug 25 17:52 UTC] No.45076637[source]▶
It's sort of frustrating that this constantly comes up. It's true that btrfs does have issues with RAID-5 and RAID-6 configurations, but this is frequently used (not necessarily by you) as some kind of gotcha as to why you shouldn't use it at all. That's insane. I promise that disk spanning issues won't affect your use of it on your tiny ThinkPad SSD.

It's important to note that striping and mirroring works just fine. It's only the 5/6 modes that are unstable: https://btrfs.readthedocs.io/en/stable/Status.html#block-gro...

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1. __turbobrew__ ◴[30 Aug 25 18:10 UTC] No.45076809[source]▶
How can I know what configurations of btrfs lose my data?

I also have had to deal with thousands of nodes kernel panicing due to a btrfs bug in linux kernel 6.8 (stable ubuntu release).

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2. ffsm8 ◴[30 Aug 25 19:06 UTC] No.45077166[source]▶
I thought the usual recommendation was to use mdadm to build the disk pool and then use btrfs on top of that - but that might be out of date. I haven't used it in a while
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3. mook ◴[31 Aug 25 03:27 UTC] No.45080111[source]▶
I thought most distros have basically disabled the footgun modes at this point; that is, using the configuration that would lose data means you'd need to work hard to get there (at which point you should have been able to see all the warnings about data loss).
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4. necheffa ◴[31 Aug 25 16:52 UTC] No.45084689[source]▶
This is very much a big compromise where you decide for yourself that storage capacity and maybe throughput are more important than anything else.

The md metadata is not adequately protected. Btrfs checksums can tell you when a file has gone bad but not self-heal. And I'm sure there are going to be caching/perf benefits left on the table not having btrfs manage all the block storage itself.

5. __turbobrew__ ◴[31 Aug 25 17:16 UTC] No.45084925[source]▶
See the part of my comment where the btrfs kernel driver paniced on Ubuntu 24 stable kernel.

We are using a fairly simple config, but under certain heavy load patterns the kernel would panic: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux...

I hear people say all the time how btrfs is stable now and people are just complaining about issues when btrfs is new, but please explain to me how the bug I linked is OK in a stable version of the most popular linux distro?