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Bcachefs: “the COW filesystem for Linux that won't eat your data”

bcachefs.org

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Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#21

Post by zanny »

I've been using btrfs since about 2011, and I've stopped using ext4 / xfs / zfs everwhere since about 2014.

From 2012-2014 it was mostly breakage every other month. From 2014-2016, it was semi-annual issues.

For the last ~18 months I have had ~30 machines running btrfs with no issues, some servers, some personal computers. The release notes are boring, the bugs are boring, and to me its definitely in a state I would strongly consider trusting it with any workload.

I worry that btrfs is just going to remain doomed. It wasn't stable half a decade ago, so it - for some reason - cannot be more stable now. But it has seen so much work put into it to make it as mature as it is now, and in my experience it is pretty damn mature now. All I want to see is another year and a half of perfect stability before I would start arguing to drop zfs entirely.

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#22

Post by rsync »

boris wrote: post #2

>Snapshot implementation has been started, but snapshots are by far the most complex of the remaining features to implement Snapshots are the #1 feature of COW filesystems. I've been using them for a bit in btrfs and this feature is game-changing (and no, it hasn't eaten my data yet).

"but snapshots are by far the most complex of the remaining features to implement"

I thought defrag (or things like defrag) was the most complicated thing to implement ?

ZFS has always had snapshots but I am told defrag is a long, long ways away ...

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#23

Post by JoshTriplett »

OD_ wrote: post #4
jethro_tell wrote: post #3

I like that we are seeing competition in this space. I think it's good for business. I do however see some big red flags in the linked page: > Starting from there, bcachefs development has prioritized incremental development, and keeping things stable, and aggressively fixing design issues as they are found Which is it? Big design changes or stable FS?

From what the developer has stated on reddit, it's more like he wants to aggressively make changes on the filesystem right now , before any attempt at mainlining into the kernel, to not end up like btrfs, which in his view, was mainlined prematurely.

It does make sense to have it rock-solid stable before mainlining, so that people don't get burned by it early on.

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#24

Post by rsync »

jethro_tell wrote: post #3

I like that we are seeing competition in this space. I think it's good for business. I do however see some big red flags in the linked page: > Starting from there, bcachefs development has prioritized incremental development, and keeping things stable, and aggressively fixing design issues as they are found Which is it? Big design changes or stable FS?

"I like that we are seeing competition in this space. I think it's good for business."

I wonder why Hans Reiser doesn't take up filesystem work again ? He has plenty of time on his hands ...

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#25

Post by _ecqc »

zanny wrote: post #21

I've been using btrfs since about 2011, and I've stopped using ext4 / xfs / zfs everwhere since about 2014. From 2012-2014 it was mostly breakage every other month. From 2014-2016, it was semi-annual issues. For the last ~18 months I have had ~30 machines running btrfs with no issues, some servers, some personal computers. The release notes are boring, the bugs are boring, and to me its definitely in a state I would…

Are you running BTRFS with its built in RAID? That's been the biggest blocker for me. There have been numerous RAID bugs that have caused data-loss and I believe at least one of them is still unpatched.

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#26

Post by aseipp »

rsync wrote: post #22
boris wrote: post #2

>Snapshot implementation has been started, but snapshots are by far the most complex of the remaining features to implement Snapshots are the #1 feature of COW filesystems. I've been using them for a bit in btrfs and this feature is game-changing (and no, it hasn't eaten my data yet).

"but snapshots are by far the most complex of the remaining features to implement" I thought defrag (or things like defrag) was the most complicated thing to implement ? ZFS has always had snapshots but I am told defrag is a long, long ways away ...

According to Kent on Reddit, bcachefs technically had online defrag since it was just bcache -- via the copying garbage collector for reclaiming space. So bcachefs will simply inherit that feature by design, which is great.

Apparently copygc is off right now because reasons, though (I'm going to assume it's almost certainly the related extent/compression issue that's holding this up from being enabled, which you can see referenced on the home page, at the bottom).

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#27

Post by sedachv »

ysleepy wrote: post #5

While I really like these sort of file systems, I'm not holding my breath. This isn't a simple filesystem project, but plays in the next-gen space ZFS opened up. There will be a lot to do, especially IO scheduling, RAID safety with shitty drive firmwares, consistency guarantees with fsync/partial flushes etc. I'm pessimistic about it being mainlined in the near future, the core team will be weary of a second btrfs. W…

> What I would like to see is a APFS/exFAT crossover with COW and data checksums without all the volume mgmt with ports for all possible operating systems so everyone can use it for their SDcards, usb-sticks and external drives without making tradeoffs and using fuse.

+1. Filesystems without bit-rot protection on flash drives are going to become at least as big a problem as optical disc rot.

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#28

Post by jdc »

zanny wrote: post #21

I've been using btrfs since about 2011, and I've stopped using ext4 / xfs / zfs everwhere since about 2014. From 2012-2014 it was mostly breakage every other month. From 2014-2016, it was semi-annual issues. For the last ~18 months I have had ~30 machines running btrfs with no issues, some servers, some personal computers. The release notes are boring, the bugs are boring, and to me its definitely in a state I would…

I lost data on my workstation running brtfs in 2016, but would give it another shot if I knew I could expect reliability from it.

Makes me wonder if anyone's tried something like Jepsen for filesystems.

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#29

Post by mschuster91 »

sedachv wrote: post #27
ysleepy wrote: post #5

While I really like these sort of file systems, I'm not holding my breath. This isn't a simple filesystem project, but plays in the next-gen space ZFS opened up. There will be a lot to do, especially IO scheduling, RAID safety with shitty drive firmwares, consistency guarantees with fsync/partial flushes etc. I'm pessimistic about it being mainlined in the near future, the core team will be weary of a second btrfs. W…

> What I would like to see is a APFS/exFAT crossover with COW and data checksums without all the volume mgmt with ports for all possible operating systems so everyone can use it for their SDcards, usb-sticks and external drives without making tradeoffs and using fuse. +1. Filesystems without bit-rot protection on flash drives are going to become at least as big a problem as optical disc rot.

> without making tradeoffs and using fuse.

What's the problem with fuse? It allows sharing code between Linux, OS X, (Free)BSD and even Windows (via dokan).

Yes, it will not offer you the same performance as an in-kernel driver (due to context switches), but given that CPU power always increases, no big problem there.

Re: Bcachefs: “the COW filesystem for Linux that won't eat your data”

#30

Post by kzrdude »

_ecqc wrote: post #25
zanny wrote: post #21

I've been using btrfs since about 2011, and I've stopped using ext4 / xfs / zfs everwhere since about 2014. From 2012-2014 it was mostly breakage every other month. From 2014-2016, it was semi-annual issues. For the last ~18 months I have had ~30 machines running btrfs with no issues, some servers, some personal computers. The release notes are boring, the bugs are boring, and to me its definitely in a state I would…

Are you running BTRFS with its built in RAID? That's been the biggest blocker for me. There have been numerous RAID bugs that have caused data-loss and I believe at least one of them is still unpatched.

I think Chris Mason is open with that raid support is not really stable yet, right?

Status page says so: https://btrfs.wiki.kernel.org/index.php/Status

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