2 ms·

Interesting although I'd have liked more summaries: there's an awful lot there. But the reasons I choose filesystems are more about reliability, failure modes,

Interesting although I'd have liked more summaries: there's an awful lot there. But the reasons I choose filesystems are more about reliability, failure modes, surrounding tooling, and so on. Btrfs fails in several critical areas: 1. No way to accurately find free space 2. catastrophic failure on write if a volume fills up, the probability of which is greater because of #1 3. repair tools usually do not recover a corrupted volume and in my testing are most likely to render as damaged volume completely unreadable, which makes #2 worse Put these things together and I can never trust Btrfs again. In the 9 years since I encountered these, I see no effort to fix them, just fooling around witg unimportant side details like performance tweaks. Fix the critical issues first then make it faster.

raegis 6d ago
Does the report say any of this? I only see "FAIL" on a few tests with ext4 and one with xfs.
- koverstreet 6d ago
  It's hard to show with any accuracy how likely a filesystem is to not break when the SHTF or something weird happens, or if they've handled all the weird corner cases, with any kind of automated test. For that you have to dig into the methodology, look at the code, look at user reports, etc. But you can get a pretty good approximation just from the philosophies and attitudes of the engineers and what they're talking about. The talk I just gave at the Rust for Linux conference was all about that - how do we make the system debugable, the community aspect of how we respond to bug reports and talk to users, the prep work for the Rust conversion and formal verification and how we're approaching all that. Reliability doesn't come out of nowhere, "all bugs are shallow with enough eyeballs" really doesn't apply to filesystems. You just have to plan for it, come up with a methodology, and do the work.
- lproven 6d ago
  It's not just me and it's had serious problems for years: https://arstechnica.com/gadgets/2021/09/examining-btrfs-linuxs-perpetually-half-finished-filesystem/ https://arstechnica.com/gadgets/2021/09/examining-btrfs-linu... <- 5Y ago. It's not materially better now. The devs are in denial about the problems because lots of big users are saying "works fine on my machine." Sure, if you have lots of backups, if you have huge volumes on huge disks and they never fill up... But it's the default in Fedora, Spiral Linux, Garuda Linux, siduction and others. Personal distros for people's own PCs and those are not well-supported enterprise kit.
  - chasil 5d ago
    SUSE also famously uses btrfs on the root file system. Don't ever let it fill up!
sandreas 6d ago
This. Btrfs blew up without ANY reason at all in my case. Rebooted and the system won't even recognize any filesystem. All btrfs tools fails to recover a single file. Here is my journey: https://forum.cgsecurity.org/phpBB3/viewtopic.php?p=39143 https://forum.cgsecurity.org/phpBB3/viewtopic.php?p=39143 I switched to ZFS and never Bad a Problem again.
- burnt-resistor 5d ago
  I used ZFS until it self-corrupted and refused to mount rw ever again. Community support was totally unhelpful and there was no resolution except buy another array and use something else. There's way too much ZFS cult fanboy glazing out there it doesn't deserve.
  - lproven 5d ago
    Now that's something I've not heard of before. On what OS? What happened, as far as you know or can tell? It would mount read-only, then? So you could copy your stuff off onto other media? Because if so, it's better than my experiences with Btrfs.
KrOctave 6d ago
This is why I have fully switched to Bcachefs, which is just way more stable and performant than btrfs

raegis 6d ago

Does the report say any of this? I only see "FAIL" on a few tests with ext4 and one with xfs.

koverstreet 6d ago
It's hard to show with any accuracy how likely a filesystem is to not break when the SHTF or something weird happens, or if they've handled all the weird corner cases, with any kind of automated test. For that you have to dig into the methodology, look at the code, look at user reports, etc. But you can get a pretty good approximation just from the philosophies and attitudes of the engineers and what they're talking about. The talk I just gave at the Rust for Linux conference was all about that - how do we make the system debugable, the community aspect of how we respond to bug reports and talk to users, the prep work for the Rust conversion and formal verification and how we're approaching all that. Reliability doesn't come out of nowhere, "all bugs are shallow with enough eyeballs" really doesn't apply to filesystems. You just have to plan for it, come up with a methodology, and do the work.
lproven 6d ago
It's not just me and it's had serious problems for years: https://arstechnica.com/gadgets/2021/09/examining-btrfs-linuxs-perpetually-half-finished-filesystem/ https://arstechnica.com/gadgets/2021/09/examining-btrfs-linu... <- 5Y ago. It's not materially better now. The devs are in denial about the problems because lots of big users are saying "works fine on my machine." Sure, if you have lots of backups, if you have huge volumes on huge disks and they never fill up... But it's the default in Fedora, Spiral Linux, Garuda Linux, siduction and others. Personal distros for people's own PCs and those are not well-supported enterprise kit.
- chasil 5d ago
  SUSE also famously uses btrfs on the root file system. Don't ever let it fill up!

sandreas 6d ago

This. Btrfs blew up without ANY reason at all in my case. Rebooted and the system won't even recognize any filesystem. All btrfs tools fails to recover a single file. Here is my journey: https://forum.cgsecurity.org/phpBB3/viewtopic.php?p=39143 https://forum.cgsecurity.org/phpBB3/viewtopic.php?p=39143 I switched to ZFS and never Bad a Problem again.

burnt-resistor 5d ago
I used ZFS until it self-corrupted and refused to mount rw ever again. Community support was totally unhelpful and there was no resolution except buy another array and use something else. There's way too much ZFS cult fanboy glazing out there it doesn't deserve.
- lproven 5d ago
  Now that's something I've not heard of before. On what OS? What happened, as far as you know or can tell? It would mount read-only, then? So you could copy your stuff off onto other media? Because if so, it's better than my experiences with Btrfs.

KrOctave 6d ago

This is why I have fully switched to Bcachefs, which is just way more stable and performant than btrfs