5 ms·

Does XFS offer benefits or tradeoffs of ZFS/ext4/others today? I have been using it with Linux since early 2000. But I am not sure how the file-system developm

Does XFS offer benefits or tradeoffs of ZFS/ext4/others today? I have been using it with Linux since early 2000. But I am not sure how the file-system development has been lately e.g. with the SSD revolution.

DiabloD3 3y ago
I think you meant ZFS, not zsh. I use both XFS and ZFS. XFS in any situation where it is a single drive (ie, my laptop), ZFS in any situation where I'm doing actual fault tolerant high performance storage stuff. I don't see where ext family really matters in modern storage. If I decide to not use XFS anymore, there are flash-dedicated filesystems that will beat ext in performance and reliability on SSDs that better fit the future.
- miohtama 3y ago
  Fixed, thank you!
- XorNot 3y ago
  ZFS is actually ideal for single drives because even if you can't do recovery, knowing a file has corrupted is extremely valuable.
  - anecdotal1 3y ago
    set copies=2 or 3 and it can recover corrupted data on that filesystem at the expense of storage
    - 5e92cb50239222b 3y ago
      SSDs are very likely to put all those copies into a single physical block underneath. Since ZFS makes backups easy, better stick to copies=1 and do backups often.
      - p01ge 3y ago
        Wrong. ZFS' copies are made across several different devices.
        vladvasiliu 3y ago
        What do you mean? The discussion in this particular sub-thread is about running ZFS on a single drive (think laptop). Does it have some kind of mechanism to send the write for a copy "later enough" that it will likely end on a different physical block?
        poige 3y ago
        I meant "primarily this copies mechanism is targeted towards multiple devices setup". With a single SSD it's indeed prone to the caveat which was pointed out; even if not due to being mapped to same storage "area" but also because SSDs often fail completely. Also makes sense to note that __when__ narrowed to a single-disk setup ZFS' can be interchanged with Btrfs; almost same set of features but lesser overhead and complexity.
      - poige 3y ago
        Wrong. ZFS' copies are made across several different devices. (2nd copy)
        krylon 3y ago
        If you are using ZFS on a single drive, they reside on the same drive by necessity. Which was the case the parent posters were talking about.
      - anecdotal1 3y ago
        I shouldn't think that's true. Why wouldn't the firmware be splitting writes across different physical chips for performance and wear leveling reasons?
- 5e92cb50239222b 3y ago
  > there are flash-dedicated filesystems that will beat ext in performance and reliability If you mean f2fs, it really won't. Be careful with it. https://www.usenix.org/system/files/atc19-jaffer.pdf https://www.usenix.org/system/files/atc19-jaffer.pdf The paper is old at this point, but I found a fresh PhD thesis from the same author from 2023, and it seems to re-confirm these findings.
  - DiabloD3 3y ago
    That sucks. I know a lot of Android users that prefer f2fs over ext* due to reliability and performance concerns, and seem to at least have some concrete reason to believe so.
- vermaden 3y ago
  Single drive ZFS is also a great use case for ZFS because: - full data integrity check (not only metadata like with XFS) - transparent compression (LZ/ZSTD/...) - ZFS Boot Environments - makes your system bulletproof against changes - easy move ZFS Boot Environments between systems with zfs send|zfs recv commands None of that is possible with XFS.
theodric 3y ago
I'm too lazy to summarize this beyond saying both ext4 and XFS have their advantages and disadvantages, and both are still under active development. ZFS is a funny and problematic one that does lots of cool tricks but isn't properly free and gobbles resources. Check this: https://linuxhint.com/xfs-vs-ext4-brief-comparison/ https://linuxhint.com/xfs-vs-ext4-brief-comparison/
- arp242 3y ago
  ZFS (or rather, OpenZFS) is absolutely Free Software and Open Source under any definition. Richard Stallman will tell you the same thing. It just has an unfortunate license that's not GPL-compatible and this causes problems with GPL kernels (e.g. Linux), which is a very different thing than "not being properly free".
  - Paul-Craft 3y ago
    Context: https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License#GPL-INCOMPATIBILITY https://en.wikipedia.org/wiki/Common_Development_and_Distrib... However, the wiki article also notes that Ubuntu includes it by default as a binary module. That seems like a sensible thing to do from a legal perspective, since it's generally accepted that binary modules are not "linked to" the kernel in such a way as to trigger GPL provisions relating to such linkage.
  - theodric 3y ago
    "Don't use ZFS. It's that simple. It was always more of a buzzword than anything else, I feel, and the licensing issues just make it a non-starter for me." -Linus Torvalds https://www.realworldtech.com/forum/?threadid=189711&curpostid=189841&ref=itsfoss.com https://www.realworldtech.com/forum/?threadid=189711&curpost...
    - stormking 3y ago
      Even Linus gets it wrong from time to time. And here he is absolutely wrong.
- 3y ago
chasil 3y ago
If you look at database benchmarks on TPC.org, you will find that many of them are on XFS (as a consequence of using RHEL/CentOS), which was designed with database performance in mind. It used to be necessary for Oracle to use raw partitions to get the very best database performance. I haven't heard of anyone doing that for many years. "The default implementation in most kernels is simply a file-global lock placed at the in-memory inode, making sure there can be only one writer per inode. Implementers of databases hate that because it limits the write concurrency on any single file to One. This is, for example, why Oracle recommends that you make tablespaces from multiple files, each no larger than one GB. "XFS, in O_DIRECT mode, removes this lock and allows atomic, concurrent writes, making database people very happy." Developers at Oracle have posted a number of blog posts on their code changes for Linux XFS. https://blogs.oracle.com/linux/post/introduction-to-xfs-transaction-mechanism https://blogs.oracle.com/linux/post/introduction-to-xfs-tran... https://blogs.oracle.com/linux/post/xfs-online-filesystem-checking https://blogs.oracle.com/linux/post/xfs-online-filesystem-ch... https://blogs.oracle.com/linux/post/xfs-2019-development-retrospective https://blogs.oracle.com/linux/post/xfs-2019-development-ret... https://blogs.oracle.com/linux/post/xfs-whats-new-and-whats-next https://blogs.oracle.com/linux/post/xfs-whats-new-and-whats-... There can be a strong bias against Oracle at HN (and I understand why) but credit must be given where it's due.
- miohtama 3y ago
  ZFS is also from Oracle, right? Seems like a dominating force in the FS industry if one can call it a such.
  - whiskeytuesday 3y ago
    I mean, in that it came out of Sun, kind of I guess.
  - chasil 3y ago
    Btrfs is the filesystem for which they are most responsible. They explicitly do not support its use for their database. "[Btrfs] was initially designed at Oracle Corporation in 2007 for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel." https://en.m.wikipedia.org/wiki/Btrfs https://en.m.wikipedia.org/wiki/Btrfs They own the rights to ZFS by way of their purchase of Sun Microsystems. Oracle is a power player in the realm of Linux filesystems, no doubt.

DiabloD3 3y ago

I think you meant ZFS, not zsh. I use both XFS and ZFS. XFS in any situation where it is a single drive (ie, my laptop), ZFS in any situation where I'm doing actual fault tolerant high performance storage stuff. I don't see where ext family really matters in modern storage. If I decide to not use XFS anymore, there are flash-dedicated filesystems that will beat ext in performance and reliability on SSDs that better fit the future.

miohtama 3y ago
Fixed, thank you!
XorNot 3y ago
ZFS is actually ideal for single drives because even if you can't do recovery, knowing a file has corrupted is extremely valuable.
- anecdotal1 3y ago
  set copies=2 or 3 and it can recover corrupted data on that filesystem at the expense of storage
  - 5e92cb50239222b 3y ago
    SSDs are very likely to put all those copies into a single physical block underneath. Since ZFS makes backups easy, better stick to copies=1 and do backups often.
    - p01ge 3y ago
      Wrong. ZFS' copies are made across several different devices.
      - vladvasiliu 3y ago
        What do you mean? The discussion in this particular sub-thread is about running ZFS on a single drive (think laptop). Does it have some kind of mechanism to send the write for a copy "later enough" that it will likely end on a different physical block?
        poige 3y ago
        I meant "primarily this copies mechanism is targeted towards multiple devices setup". With a single SSD it's indeed prone to the caveat which was pointed out; even if not due to being mapped to same storage "area" but also because SSDs often fail completely. Also makes sense to note that __when__ narrowed to a single-disk setup ZFS' can be interchanged with Btrfs; almost same set of features but lesser overhead and complexity.
    - poige 3y ago
      Wrong. ZFS' copies are made across several different devices. (2nd copy)
      - krylon 3y ago
        If you are using ZFS on a single drive, they reside on the same drive by necessity. Which was the case the parent posters were talking about.
    - anecdotal1 3y ago
      I shouldn't think that's true. Why wouldn't the firmware be splitting writes across different physical chips for performance and wear leveling reasons?
5e92cb50239222b 3y ago
> there are flash-dedicated filesystems that will beat ext in performance and reliability If you mean f2fs, it really won't. Be careful with it. https://www.usenix.org/system/files/atc19-jaffer.pdf https://www.usenix.org/system/files/atc19-jaffer.pdf The paper is old at this point, but I found a fresh PhD thesis from the same author from 2023, and it seems to re-confirm these findings.
- DiabloD3 3y ago
  That sucks. I know a lot of Android users that prefer f2fs over ext* due to reliability and performance concerns, and seem to at least have some concrete reason to believe so.
vermaden 3y ago
Single drive ZFS is also a great use case for ZFS because: - full data integrity check (not only metadata like with XFS) - transparent compression (LZ/ZSTD/...) - ZFS Boot Environments - makes your system bulletproof against changes - easy move ZFS Boot Environments between systems with zfs send|zfs recv commands None of that is possible with XFS.

theodric 3y ago

I'm too lazy to summarize this beyond saying both ext4 and XFS have their advantages and disadvantages, and both are still under active development. ZFS is a funny and problematic one that does lots of cool tricks but isn't properly free and gobbles resources. Check this: https://linuxhint.com/xfs-vs-ext4-brief-comparison/ https://linuxhint.com/xfs-vs-ext4-brief-comparison/

arp242 3y ago
ZFS (or rather, OpenZFS) is absolutely Free Software and Open Source under any definition. Richard Stallman will tell you the same thing. It just has an unfortunate license that's not GPL-compatible and this causes problems with GPL kernels (e.g. Linux), which is a very different thing than "not being properly free".
- Paul-Craft 3y ago
  Context: https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License#GPL-INCOMPATIBILITY https://en.wikipedia.org/wiki/Common_Development_and_Distrib... However, the wiki article also notes that Ubuntu includes it by default as a binary module. That seems like a sensible thing to do from a legal perspective, since it's generally accepted that binary modules are not "linked to" the kernel in such a way as to trigger GPL provisions relating to such linkage.
- theodric 3y ago
  "Don't use ZFS. It's that simple. It was always more of a buzzword than anything else, I feel, and the licensing issues just make it a non-starter for me." -Linus Torvalds https://www.realworldtech.com/forum/?threadid=189711&curpostid=189841&ref=itsfoss.com https://www.realworldtech.com/forum/?threadid=189711&curpost...
  - stormking 3y ago
    Even Linus gets it wrong from time to time. And here he is absolutely wrong.
3y ago

chasil 3y ago

If you look at database benchmarks on TPC.org, you will find that many of them are on XFS (as a consequence of using RHEL/CentOS), which was designed with database performance in mind. It used to be necessary for Oracle to use raw partitions to get the very best database performance. I haven't heard of anyone doing that for many years. "The default implementation in most kernels is simply a file-global lock placed at the in-memory inode, making sure there can be only one writer per inode. Implementers of databases hate that because it limits the write concurrency on any single file to One. This is, for example, why Oracle recommends that you make tablespaces from multiple files, each no larger than one GB. "XFS, in O_DIRECT mode, removes this lock and allows atomic, concurrent writes, making database people very happy." Developers at Oracle have posted a number of blog posts on their code changes for Linux XFS. https://blogs.oracle.com/linux/post/introduction-to-xfs-transaction-mechanism https://blogs.oracle.com/linux/post/introduction-to-xfs-tran... https://blogs.oracle.com/linux/post/xfs-online-filesystem-checking https://blogs.oracle.com/linux/post/xfs-online-filesystem-ch... https://blogs.oracle.com/linux/post/xfs-2019-development-retrospective https://blogs.oracle.com/linux/post/xfs-2019-development-ret... https://blogs.oracle.com/linux/post/xfs-whats-new-and-whats-next https://blogs.oracle.com/linux/post/xfs-whats-new-and-whats-... There can be a strong bias against Oracle at HN (and I understand why) but credit must be given where it's due.

miohtama 3y ago
ZFS is also from Oracle, right? Seems like a dominating force in the FS industry if one can call it a such.
- whiskeytuesday 3y ago
  I mean, in that it came out of Sun, kind of I guess.
- chasil 3y ago
  Btrfs is the filesystem for which they are most responsible. They explicitly do not support its use for their database. "[Btrfs] was initially designed at Oracle Corporation in 2007 for use in Linux, and since November 2013, the file system's on-disk format has been declared stable in the Linux kernel." https://en.m.wikipedia.org/wiki/Btrfs https://en.m.wikipedia.org/wiki/Btrfs They own the rights to ZFS by way of their purchase of Sun Microsystems. Oracle is a power player in the realm of Linux filesystems, no doubt.