[pfexec]

Because every time btrfs is mentioned, 5 more people come out of the woodwork saying that it irreparably lost all their data. Sorry but there's just too many stories for it to be mere coincidences.

Your statement is misleading. No one is using btrfs on servers. Debian and Ubuntu use ext4 by default. RHEL removed support for btrfs long ago, and it's not coming back:

> Red Hat will not be moving Btrfs to a fully supported feature. It was fully removed in Red Hat Enterprise Linux 8.

[accelbred]

AFAIK, Facebook uses BTRFS on their servers.

[mdedetrich]

They do, but this is misleading due to a number of caveats

First one is that they don't use btrfs own RAID (aka btrfs-raid/volume management). They actually use hardware RAID so they don't experience any of the stability/data integrity issues people experience with btrfs-raid. Ontop of this, facebooks servers run in data centers that have 100% electricity uptime (these places have diesel generators for backup electricity)

Synology likewise offers btrfs on their NAS, but its underneath mdadm (software RAID)

The main benefit that Facebook gets from btrfs is transparent compression and snapshots and thats about it.

[ChocolateGod]

In a scenario where they don't have to worry about data going poof because it's used to run stateless containers (taking advantage of CoW to reduce startup time etc)

[reissbaker]

Ex-Meta employee here, and yup — this is true.

[o11c]

And they almost always 'forget' to mention "that was in 2010" or "I was using the BTRFS feature marked 'do not use, unstable'".

It's really difficult to get a real feel for BTRFS when people deliberately omit critical information about their experiences. Certainly I haven't had any problems (unless you count the time it detected some bitrot on a hard drive and I had to restore some files from a backup - obviously this was in "single" mode).

[plqbfbv]

My fairly recent experience with some timelines, posted 20d ago: https://news.ycombinator.com/item?id=45210911

Some of the most catastrophic ones were 3 years ago or earlier, but the latest kernel bug (point 5) was with 6.16.3, ~1 month ago. It did recover, but I already mentally prepared to a night of restores from backups...

[jeltz]

One of the PostgreSQL devs managed to corrupt Btrfs about 2 years ago when working on async IO. Is that recent enough?

[newZWhoDis]

Synology exclusively uses BTRFS afaik, and there aren't widespread stories of data loss with their products.

[pfexec]

Took 10 seconds to find:

https://philip.greenspun.com/blog/2024/02/29/why-is-the-btrf...

> We had a few seconds of power loss the other day. Everything in the house, including a Windows machine using NTFS, came back to life without any issues. A Synology DS720+, however, became a useless brick, claiming to have suffered unrecoverable file system damage while the underlying two hard drives and two SSDs are in perfect condition. It’s two mirrored drives using the Btrfs file system

[mdedetrich]

Thats because they use mdadm for the RAID, the btrfs sits underneath a virtual mdadm volume ;)

[danw1979]

And also, I've read plenty enough about how hard it has been to maintain btrfs over the years. It's never really felt like the future.

Plus I needed zvols for various applications. I've used ZFS on BSD for even longer so when OpenZFS reached a decent level of maturity the choice between that and btrfs was obvious for me.

[teiferer]

The argument of zvols doesn't really fit in here Unless bcachefs supports them?

[bakugo]

Not really data loss per se, but let me add my own story to the pile: just last week, I had a btrfs filesystem error out and go permanently read-only simply due to the disk becoming full. Hours of searching and no solution to be found, had to be reformatted.

I don't understand how btrfs is considered by some people to be stable enough for production use.

[lupusreal]

I know somebody is going to say otherwise, but BTRFS seems genuinely rock solid in single-disk setups. OpenSUSE defaults to it so I've been using it for years. No problems, it's not even something I worry about.

[chasil]

Allowing btrfs to run out of space is well known to do irreparable damage.

Keeping it healthy means paying close attention to "btrfs fi df" and/or "fi usage" for best results.

ZFS also does not react well to running out of space.