[manuel_w]

Discussions on checksumming filesystems usually revolve around ZFS and BTRFS, but has someone any experience with bcachefs? It's upstreamed in the linux kernel, I learned, and is supposed to have full checksumming. The author also seems to take filesystem responsibility seriously.

Is anyone using it around here?

https://bcachefs.org/

[ffsm8]

I tried it out on my homelab server right after the merge into the Linux kernel.

Took roughly one week for the whole raid to stop mounting because of the journal (8hdd, 2 ssd write cache, 2 nvme read cache).

The author responded on Reddit within a day, I tried his fix, (which meant compiling the Linux kernel and booting from that), but his fix didn't resolve the issue. He sadly didn't respond after that, so I wiped and switched back to a plain mdadmin raid after a few days of waiting.

I had everything important backed up, obviously (though I did lose some unimportant data), but it did remind me that bleeding edge is indeed ... Unstable

The setup process and features are fantastic however, simply being able to add a disk and flag it as read/write cache feels great. I'm certain I'll give it another try in a few years, after it had some time in the oven.

[iforgotpassword]

New filesystems seems to have a chicken and egg problem really. It's not like switching from Nvidia's proprietary drivers to nouveau and then back if it turns out they don't work that well. Switching filesystems, especially in larger raid setups where you desperately need more testing and real world usage feedback, is pretty involved, and even if you have everything backed up it's pretty time consuming restoring everything should things go haywire.

And even if you have the time and patience to be one of these early adopters, debugging any issues encountered might also be difficult, as ideally you want to give the devs full access to your filesystem for debugging and attempted fixes, which is obviously not always feasible.

So anything beyond the most trivial setups and usage patterns gets a miniscule amount of testing.

In an ideal world, you'd nail your FS design first try, make no mistakes during implementation and call it a day. I'd like to live in an ideal world.

[clan]

That was a decision Linus regretted[1]. There has been some recent discussion about this here on Hacker News[2].

[1] https://linuxiac.com/torvalds-expresses-regret-over-merging-...

[2] https://news.ycombinator.com/item?id=41407768

[Ygg2]

Context. Linux regrets it because bcachefs doesn't have same commitment to stability as Linux.

Kent wants to fix a bug with large PR

Linux doesn't want to merge and review PR that touches so many non-bcachefs things.

They're both right in a way. Kent wants bcachefs to be stable/work good, Linus wants Linux to be stable.

[CooCooCaCha]

After reading the email chain I have to say my enthusiasm for bcachefs has diminished significantly. I had no idea Kent was that stubborn and seems to have little respect for Linus or his rules.

[homebrewer]

As usual, the top comments in that submission are very biased. I think HN should sort comments in a random order in every polarizing discussion. Anyone reading this, do yourself a favor and dig through both links, or ignore the parent's comment altogether.

Linus "regretted" it in the sense "it was a bit too early because bcachefs is moving at such a fast speed", and not in the sense "we got a second btrfs that eats your data for lunch".

Please provide context and/or short human-friendly explanation, because I'm pretty sure most readers won't go further than your comment and will remember it as "Linus regrets merging bcachefs", helping spread FUD for years down the line.

[olavgg]

It is marked experimental, and since it was merged into the kernel there have been a few major issues that has been resolved. I wouldn't risk production data on it, but for a home lab it could be fine. But you need to ask yourself, how much time are you willing to spend if something should go wrong? I have also been running ZFS for 15+ years, and I've seen a lot of crap because of bad hardware. But with good enterprise hardware it has been working flawless.

[eru]

I'm using it. It's been ok so far, but you should have all your data backed up anyway, just in case.

I'm trying a combination where I have an SSD (of about 2TiB) in front of a big hard drive (about 8 TiB) and using the SSD as a cache.

[tekknik]

i do this on my synoligy using btrfs. i’m still not convinced SSD caching gives any benefit for a home user. 5 spindle drives can already read and write faster than line rate on the NIC (1gbe) so what is the point of adding another failure point?

[DistractionRect]

I'm optimistic about it, but probably won't switch over my home lab for a while. I've had quirks with my (now legacy) zsys + zfs on root for Ubuntu, but since it's a common config//widely used for years it's pretty easy to find support.

I probably won't use bcachefs until a similar level of adoption/community support exists.

[rollcat]

Can't comment on bcachefs (I think it's still early), but I've been running with bcache in production on one "canary" machine for years, and it's been rock-solid.