4 ms·

Is BTRFS rapidly gaining feature and reliability parity with ZFS?

trillic 4y ago
for desktop use-cases, I think so. I'm BTRFS everywhere at home now, even my NAS. All RAID1, backups to object storage.
AdmiralAsshat 4y ago
BTRFS seemingly still has problems, see: https://arstechnica.com/gadgets/2021/09/examining-btrfs-linuxs-perpetually-half-finished-filesystem/ https://arstechnica.com/gadgets/2021/09/examining-btrfs-linu... but for desktop use, it's probably fine. It's been the default for new Fedora installations for over a year now, and I don't see too many Fedora users complaining about their filesystem being hosed. My current installation is still legacy EXT4 since I upgrade, but at some point I might blow it away and try a fresh install.
adrian_b 4y ago
BTRFS might be gaining feature and reliability parity with ZFS, but I have never heard of any advantage of BTRFS over ZFS and in all the benchmarks that I have ever seen BTRFS is much slower than ZFS. When the file system performance is important, XFS and EXT4 are the fastest. When the extra features provided by ZFS are important, it becomes the appropriate choice. For BTRFS, I am not aware of any application for which it would be the right choice.
- quotemstr 4y ago
  Last time I checked, ZFS duplicated the OS page cache and didn't support defragmentation. Is that still the case?
  - vkaku 4y ago
    I understand the first one may be a genuine pptimization needed. But for the second one: when a file is striped across different physical disks with possibly different characteristics, how would you defrag it without knowing the read access pattern?
    - Dylan16807 4y ago
      > when a file is striped across different physical disks with possibly different characteristics, how would you defrag it without knowing the read access pattern? Looking at a single disk at a time, do your best to make sure all chunks of the same file are in order and adjacent. You could be smarter than that, but just that would do fine. The problem is that ZFS basically can't move things.
      - ender341341 4y ago
        > The problem is that ZFS basically can't move things. The one killer feature for me with btrfs is offline deduping (and by extension not having de-duping require a super computer to run). My data has enough duplication that it'd be nice to have, but not worth requiring hundreds of gigs of ram. Being able to fire off a job after importing a large set of data (or maybe yearly-ish) would be awesome and give me a few extra years without having to update my hardware.
      - vkaku 4y ago
        That doesn't account for physical disk characteristics at all. You could have disks from different generations all be part of a pool, CMR vs SMR(!) (needs zone resets and large chunk writes), disks could degrade etc. Plus, when you update a file, you literally create new links and update the file out of place (true for any COW FS). So the read won't be sequential if you want to access two versions at the same time. In that case you want to know if you optimize for hardware failure as opposed to for performance. This could be fixed for specific usecases but not all block patterns in general. Just why I posted this.
    - mappu 4y ago
      It's not possible to fix the first one (to merge the ARC with the Linux page cache), because the necessary page cache internals are GPL-only.
      - quotemstr 4y ago
        In that case, I'd need ZFS to provide a way to disable ARC: double caching isn't acceptable to me.
  - jraph 4y ago
    I don't know ZFS, I have been using Btrfs for years (desktop, simple setup). Defragmentation in Btrfs is not without issues. If you use subvolume (and I use Btrfs for subvolumes) and in particular snapshots, defragmenting a subvolume will deduplicate its files, increasing disk usage. On the other hand, I have not had much need for defragmenting.
  - mustache_kimono 4y ago
    > ZFS duplicated the OS page cache Only in very limited instances. I think ZFS duplicates the inodes and dentries cache, and only file pages when you do something like mmap a file.
- nicolaslem 4y ago
  > I have never heard of any advantage of BTRFS over ZFS. The ability to add capacity to a pool by adding a single drive at a time, or the fact that it is readily available on any Linux box.
  - kadoban 4y ago
    > The ability to add capacity to a pool by adding a single drive at a time zfs supports that now
    - derkades 4y ago
      I think you are referring to RAIDZ expansion, which isn't merged yet? https://github.com/openzfs/zfs/pull/12225 https://github.com/openzfs/zfs/pull/12225
      - deleted 4y ago
        [deleted]
      - kadoban 4y ago
        Hm, thanks. Yeah, I thought it was already released. The thing I read said "implemented", I guess I took the wrong meaning from that.
- intuxikated 4y ago
  Any application on linux where snapshots, resizable partitions, compression or deduplication is useful? Zfs on linux is still not ready for primetime on root partitions, and for most uses except raid5/6 (which isn't important for 99% of desktop users) btrfs is an excellent option There's a reason the other major non-debian distros have switched to it by default. I'm still waiting for ubuntu to allow installing using btrfs + fulldisk encryption by default, which is currently a massive issue.
  - aeadio 4y ago
    > Zfs on linux is still not ready for primetime on root partitions Not sure where you got this from. OpenZFS on Linux is considered stable by the project. It has been rock solid, free of major issues, and considered more than ready for prime time since at least 0.8, and probably much earlier. It’s now at 2.1. I’ve been using it across multiple environments, including my personal laptop and workstation which maintained the same root-on-ZFS install for 6+ years, including 2 full migrations to new hardware using zfs send. I’ve deployed much larger pools in professional settings and they’ve been rock solid. Btrfs has had numerous data loss issues in that time. I can only recall one data loss issue in a ZFS on Linux release, several years ago, which was caught very quickly.
    - intuxikated 4y ago
      Which major distro allows using ZFS from its official installer except ubuntu (now deprecated) and maybe arch linux? Which distro uses ZFS by default? I think almost none. Sure, ZFS might be stable for extra mass storage disks, but how many people use it as a filesystem for the linux root? Never seen anyone putting the main OS on zfs Btrfs hasn't had any major data loss issues for the last 5 years (excluding the raid issues) btrfs is much newer than ZFS, so obviously it took longer to be stable, if you're talking about 6+ years ago, Btrfs was obviously not ready yet, but now? It's been the default on OpenSUSE for 5 years and Fedora for 2.
      - mustache_kimono 4y ago
        > Never seen anyone putting the main OS on zfs “I can’t believe Nixon won. I don’t know anyone who voted for him.” -- Pauline Kael I use ZFS on root. Know lots of people who do. Might be your bubble?
orra 4y ago
Depends on your use case, but for me, absolutely not. The btrfs manual says RAID5 “should not be used in production, only for evaluation or testing. The power failure safety for metadata with RAID56 is not 100%.”

for desktop use-cases, I think so. I'm BTRFS everywhere at home now, even my NAS. All RAID1, backups to object storage.

BTRFS seemingly still has problems, see: https://arstechnica.com/gadgets/2021/09/examining-btrfs-linuxs-perpetually-half-finished-filesystem/ https://arstechnica.com/gadgets/2021/09/examining-btrfs-linu... but for desktop use, it's probably fine. It's been the default for new Fedora installations for over a year now, and I don't see too many Fedora users complaining about their filesystem being hosed. My current installation is still legacy EXT4 since I upgrade, but at some point I might blow it away and try a fresh install.

adrian_b 4y ago

BTRFS might be gaining feature and reliability parity with ZFS, but I have never heard of any advantage of BTRFS over ZFS and in all the benchmarks that I have ever seen BTRFS is much slower than ZFS. When the file system performance is important, XFS and EXT4 are the fastest. When the extra features provided by ZFS are important, it becomes the appropriate choice. For BTRFS, I am not aware of any application for which it would be the right choice.

quotemstr 4y ago
Last time I checked, ZFS duplicated the OS page cache and didn't support defragmentation. Is that still the case?
- vkaku 4y ago
  I understand the first one may be a genuine pptimization needed. But for the second one: when a file is striped across different physical disks with possibly different characteristics, how would you defrag it without knowing the read access pattern?
  - Dylan16807 4y ago
    > when a file is striped across different physical disks with possibly different characteristics, how would you defrag it without knowing the read access pattern? Looking at a single disk at a time, do your best to make sure all chunks of the same file are in order and adjacent. You could be smarter than that, but just that would do fine. The problem is that ZFS basically can't move things.
    - ender341341 4y ago
      > The problem is that ZFS basically can't move things. The one killer feature for me with btrfs is offline deduping (and by extension not having de-duping require a super computer to run). My data has enough duplication that it'd be nice to have, but not worth requiring hundreds of gigs of ram. Being able to fire off a job after importing a large set of data (or maybe yearly-ish) would be awesome and give me a few extra years without having to update my hardware.
    - vkaku 4y ago
      That doesn't account for physical disk characteristics at all. You could have disks from different generations all be part of a pool, CMR vs SMR(!) (needs zone resets and large chunk writes), disks could degrade etc. Plus, when you update a file, you literally create new links and update the file out of place (true for any COW FS). So the read won't be sequential if you want to access two versions at the same time. In that case you want to know if you optimize for hardware failure as opposed to for performance. This could be fixed for specific usecases but not all block patterns in general. Just why I posted this.
  - mappu 4y ago
    It's not possible to fix the first one (to merge the ARC with the Linux page cache), because the necessary page cache internals are GPL-only.
    - quotemstr 4y ago
      In that case, I'd need ZFS to provide a way to disable ARC: double caching isn't acceptable to me.
- jraph 4y ago
  I don't know ZFS, I have been using Btrfs for years (desktop, simple setup). Defragmentation in Btrfs is not without issues. If you use subvolume (and I use Btrfs for subvolumes) and in particular snapshots, defragmenting a subvolume will deduplicate its files, increasing disk usage. On the other hand, I have not had much need for defragmenting.
- mustache_kimono 4y ago
  > ZFS duplicated the OS page cache Only in very limited instances. I think ZFS duplicates the inodes and dentries cache, and only file pages when you do something like mmap a file.
nicolaslem 4y ago
> I have never heard of any advantage of BTRFS over ZFS. The ability to add capacity to a pool by adding a single drive at a time, or the fact that it is readily available on any Linux box.
- kadoban 4y ago
  > The ability to add capacity to a pool by adding a single drive at a time zfs supports that now
  - derkades 4y ago
    I think you are referring to RAIDZ expansion, which isn't merged yet? https://github.com/openzfs/zfs/pull/12225 https://github.com/openzfs/zfs/pull/12225
    - deleted 4y ago
      [deleted]
    - kadoban 4y ago
      Hm, thanks. Yeah, I thought it was already released. The thing I read said "implemented", I guess I took the wrong meaning from that.
intuxikated 4y ago
Any application on linux where snapshots, resizable partitions, compression or deduplication is useful? Zfs on linux is still not ready for primetime on root partitions, and for most uses except raid5/6 (which isn't important for 99% of desktop users) btrfs is an excellent option There's a reason the other major non-debian distros have switched to it by default. I'm still waiting for ubuntu to allow installing using btrfs + fulldisk encryption by default, which is currently a massive issue.
- aeadio 4y ago
  > Zfs on linux is still not ready for primetime on root partitions Not sure where you got this from. OpenZFS on Linux is considered stable by the project. It has been rock solid, free of major issues, and considered more than ready for prime time since at least 0.8, and probably much earlier. It’s now at 2.1. I’ve been using it across multiple environments, including my personal laptop and workstation which maintained the same root-on-ZFS install for 6+ years, including 2 full migrations to new hardware using zfs send. I’ve deployed much larger pools in professional settings and they’ve been rock solid. Btrfs has had numerous data loss issues in that time. I can only recall one data loss issue in a ZFS on Linux release, several years ago, which was caught very quickly.
  - intuxikated 4y ago
    Which major distro allows using ZFS from its official installer except ubuntu (now deprecated) and maybe arch linux? Which distro uses ZFS by default? I think almost none. Sure, ZFS might be stable for extra mass storage disks, but how many people use it as a filesystem for the linux root? Never seen anyone putting the main OS on zfs Btrfs hasn't had any major data loss issues for the last 5 years (excluding the raid issues) btrfs is much newer than ZFS, so obviously it took longer to be stable, if you're talking about 6+ years ago, Btrfs was obviously not ready yet, but now? It's been the default on OpenSUSE for 5 years and Fedora for 2.
    - mustache_kimono 4y ago
      > Never seen anyone putting the main OS on zfs “I can’t believe Nixon won. I don’t know anyone who voted for him.” -- Pauline Kael I use ZFS on root. Know lots of people who do. Might be your bubble?

orra 4y ago

Depends on your use case, but for me, absolutely not. The btrfs manual says RAID5 “should not be used in production, only for evaluation or testing. The power failure safety for metadata with RAID56 is not 100%.”