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Can you comment on btrfs by comparison? Also, what is the status of the license incompatibility/integration of ZFS with distros? Canonical seems to think that s

Can you comment on btrfs by comparison? Also, what is the status of the license incompatibility/integration of ZFS with distros? Canonical seems to think that shipping it with ubuntu is legal, but other distros seem less sure.

spindle 6y ago
It's trivial to use ZFS on NixOS, including on the root partition. The legal position is that ZFS is open source under a copyleft license but that many people think that it's illegal to bundle it with the Linux kernel because of some (I think unintended) incompatibilities between its license and the Linux kernel's license. Canonical (and some others) disagree, and think that it's legal. It's only the bundling that's at issue - everyone agrees that it's legal to use with Linux once you have both. See https://ubuntu.com/blog/zfs-licensing-and-linux https://ubuntu.com/blog/zfs-licensing-and-linux for Canonical's opinion.
- viraptor 6y ago
  https://www.gnu.org/licenses/license-list.html#CDDL https://www.gnu.org/licenses/license-list.html#CDDL "This means a module covered by the GPL and a module covered by the CDDL cannot legally be linked together." I don't think the incompatibilities are really unintended. If anyone has enough lawyers and money to relicense something correctly, it's Oracle.
  - trasz 6y ago
    Except then you'd loose the patent protection provided by CDDL. And you'd cause licensing problems for literally everyone else but Linux. And you probably wouldn't gain anything in the long run anyway; AdvFS was released under GPL and went nowhere.
- capitol_ 6y ago
  The incompatibility was very much intended, Sun needed a way to compete with linux and didn't want to be assimilated into the linux ecosystem, so they released opensolaris under CDDL instead of GPL or MIT. Oracle haven't re-licensed it for their own reasons. Here is some more info on the subject: https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/ https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/
  - throw0101a 6y ago
    > The incompatibility was very much intended Nope. Simon Phipps, Sun's Chief Open Source Officer at the time, and the boss of Danese Cooper—who is the source of the claims it was intended—has stated it was not: * https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License#GPL_compatibility https://en.wikipedia.org/wiki/Common_Development_and_Distrib... Brian Cantrill, the co-author of Dtrace, has also stated that that they were expecting the Linux folks to potentially incorporate their work: * https://old.reddit.com/r/IAmA/comments/31ny87#cq3bs9z https://old.reddit.com/r/IAmA/comments/31ny87#cq3bs9z Do you have any citations that can corroborate the/your claim that incompatibility was intended? > Here is some more info on the subject: See also: * https://softwarefreedom.org/resources/2016/linux-kernel-cddl.html https://softwarefreedom.org/resources/2016/linux-kernel-cddl...
    - Wowfunhappy 6y ago
      Do you happen to know where the claim that it was intended came from?
      - ghaff 6y ago
        Because Danese Cooper said so. (See video link from the Wikipedia article: https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License https://en.wikipedia.org/wiki/Common_Development_and_Distrib...) I think there's also a general suspicion that Sun could have just chosen the GPL if they cared about compatibility. Although, for various reasons, it's probably at least somewhat more complicated than that because of patent protection, etc.
        rleigh 6y ago
        "Sun could have just chosen the GPL if they cared about compatibility." That's a very loaded statement. I've seen it said quite a lot over the years. But, have you thought about its implications? The implicit assumption here is the primacy of the GPL over all other open source licences. Why should other companies and organisations treat it as "more special" than any other free/open source licence when it comes down to interoperability? When it comes down to compatibility, the GPL is one of the last licences you should choose. Because by its very nature it is deliberately and intentionally incompatible with everything other than the most permissive licences. The problem with "viral" licences like the GPL is that "there can only be one" because they are mutually incompatible by nature. Why should the MPL/Apache/CDDL licences make special exemptions to lessen their requirements so that they can be GPL-compatible?
- trasz 6y ago
  FWIW, CDDL is pretty much just Mozilla license. The incompatibility is caused by GPL, which, according to FSF, cannot be linked against anything that's not a subset of GPL. You'd get the same incompatibility if ZFS was covered by GPLv3, for example.
- nabla9 6y ago
  Even if canonical would be wrong it seems that the change that anyone having a interest to sue Canonical over unintended legal technicality is nil. ZFS on Linux does not break the intention and spirit of the kernel licence.
  - luma 6y ago
    Relying on Oracle not to sue people for questionable reasons seems like a precarious position.
    - vetinari 6y ago
      Or Linux Kernel people. If you are distributing their work, you can do it because GPL allows it. But for GPL to allow it, you cannot break it or ignore it, otherwise you will lose the distribution rights.
    - trasz 6y ago
      So basically the problem with ZFS is that Oracle would sue someone for GPL violation?
viraptor 6y ago
Btrfs has pretty much the same features listed above minus the cache drive handling. (You can still get the cache drive behaviour over bcache device) The raid has different modes, so you'll have to decide if what's available is enough for you. You can check the status of each feature here: https://btrfs.wiki.kernel.org/index.php/Status https://btrfs.wiki.kernel.org/index.php/Status
- mapgrep 6y ago
  It’s also still considered experimental and according to kernel.org wiki “under heavy development.” ZFS was released for production use 14 years ago.
  - viraptor 6y ago
    https://github.com/torvalds/linux/blob/master/fs/btrfs/Kconfig https://github.com/torvalds/linux/blob/master/fs/btrfs/Kconf... None of the options are marked experimental. (Specific features are marked unstable on the status page) "Under heavy development" does not mean anything about stability. The kernel itself is under heavy development. ZoL is under heavy development. The disk format is stable, which is what matters. SUSE provides commercial support for btrfs and uses it as the default. That's pretty much as non-experimental as is gets.
    - mapgrep 6y ago
      In the past, when data integrity issues emerged, btrfs devs have stated that it is not ready for production. Has there been an announcement to the contrary? If btrfs is production ready, is this clearly stated somewhere? Solaris has defaulted to ZFS at least since version 11 first released eight years ago. Update - also it appears Suse enterprise uses btrfs for the root os filesystem but xfs for everything else including by default /home. To me, this seems telling? If it’s so solid why not use it for /home?
  - deleted 6y ago
    [deleted]
curt15 6y ago
Fedora is proposing to default to btrfs for its next release: https://fedoraproject.org/wiki/Changes/BtrfsByDefault https://fedoraproject.org/wiki/Changes/BtrfsByDefault
- throw0101a 6y ago
  Contrast with Debian's warnings on the topic: * https://wiki.debian.org/Btrfs#Warnings https://wiki.debian.org/Btrfs#Warnings

spindle 6y ago

It's trivial to use ZFS on NixOS, including on the root partition. The legal position is that ZFS is open source under a copyleft license but that many people think that it's illegal to bundle it with the Linux kernel because of some (I think unintended) incompatibilities between its license and the Linux kernel's license. Canonical (and some others) disagree, and think that it's legal. It's only the bundling that's at issue - everyone agrees that it's legal to use with Linux once you have both. See https://ubuntu.com/blog/zfs-licensing-and-linux https://ubuntu.com/blog/zfs-licensing-and-linux for Canonical's opinion.

viraptor 6y ago
https://www.gnu.org/licenses/license-list.html#CDDL https://www.gnu.org/licenses/license-list.html#CDDL "This means a module covered by the GPL and a module covered by the CDDL cannot legally be linked together." I don't think the incompatibilities are really unintended. If anyone has enough lawyers and money to relicense something correctly, it's Oracle.
- trasz 6y ago
  Except then you'd loose the patent protection provided by CDDL. And you'd cause licensing problems for literally everyone else but Linux. And you probably wouldn't gain anything in the long run anyway; AdvFS was released under GPL and went nowhere.
capitol_ 6y ago
The incompatibility was very much intended, Sun needed a way to compete with linux and didn't want to be assimilated into the linux ecosystem, so they released opensolaris under CDDL instead of GPL or MIT. Oracle haven't re-licensed it for their own reasons. Here is some more info on the subject: https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/ https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/
- throw0101a 6y ago
  > The incompatibility was very much intended Nope. Simon Phipps, Sun's Chief Open Source Officer at the time, and the boss of Danese Cooper—who is the source of the claims it was intended—has stated it was not: * https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License#GPL_compatibility https://en.wikipedia.org/wiki/Common_Development_and_Distrib... Brian Cantrill, the co-author of Dtrace, has also stated that that they were expecting the Linux folks to potentially incorporate their work: * https://old.reddit.com/r/IAmA/comments/31ny87#cq3bs9z https://old.reddit.com/r/IAmA/comments/31ny87#cq3bs9z Do you have any citations that can corroborate the/your claim that incompatibility was intended? > Here is some more info on the subject: See also: * https://softwarefreedom.org/resources/2016/linux-kernel-cddl.html https://softwarefreedom.org/resources/2016/linux-kernel-cddl...
  - Wowfunhappy 6y ago
    Do you happen to know where the claim that it was intended came from?
    - ghaff 6y ago
      Because Danese Cooper said so. (See video link from the Wikipedia article: https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License https://en.wikipedia.org/wiki/Common_Development_and_Distrib...) I think there's also a general suspicion that Sun could have just chosen the GPL if they cared about compatibility. Although, for various reasons, it's probably at least somewhat more complicated than that because of patent protection, etc.
      - rleigh 6y ago
        "Sun could have just chosen the GPL if they cared about compatibility." That's a very loaded statement. I've seen it said quite a lot over the years. But, have you thought about its implications? The implicit assumption here is the primacy of the GPL over all other open source licences. Why should other companies and organisations treat it as "more special" than any other free/open source licence when it comes down to interoperability? When it comes down to compatibility, the GPL is one of the last licences you should choose. Because by its very nature it is deliberately and intentionally incompatible with everything other than the most permissive licences. The problem with "viral" licences like the GPL is that "there can only be one" because they are mutually incompatible by nature. Why should the MPL/Apache/CDDL licences make special exemptions to lessen their requirements so that they can be GPL-compatible?
trasz 6y ago
FWIW, CDDL is pretty much just Mozilla license. The incompatibility is caused by GPL, which, according to FSF, cannot be linked against anything that's not a subset of GPL. You'd get the same incompatibility if ZFS was covered by GPLv3, for example.
nabla9 6y ago
Even if canonical would be wrong it seems that the change that anyone having a interest to sue Canonical over unintended legal technicality is nil. ZFS on Linux does not break the intention and spirit of the kernel licence.
- luma 6y ago
  Relying on Oracle not to sue people for questionable reasons seems like a precarious position.
  - vetinari 6y ago
    Or Linux Kernel people. If you are distributing their work, you can do it because GPL allows it. But for GPL to allow it, you cannot break it or ignore it, otherwise you will lose the distribution rights.
  - trasz 6y ago
    So basically the problem with ZFS is that Oracle would sue someone for GPL violation?

viraptor 6y ago

Btrfs has pretty much the same features listed above minus the cache drive handling. (You can still get the cache drive behaviour over bcache device) The raid has different modes, so you'll have to decide if what's available is enough for you. You can check the status of each feature here: https://btrfs.wiki.kernel.org/index.php/Status https://btrfs.wiki.kernel.org/index.php/Status

mapgrep 6y ago
It’s also still considered experimental and according to kernel.org wiki “under heavy development.” ZFS was released for production use 14 years ago.
- viraptor 6y ago
  https://github.com/torvalds/linux/blob/master/fs/btrfs/Kconfig https://github.com/torvalds/linux/blob/master/fs/btrfs/Kconf... None of the options are marked experimental. (Specific features are marked unstable on the status page) "Under heavy development" does not mean anything about stability. The kernel itself is under heavy development. ZoL is under heavy development. The disk format is stable, which is what matters. SUSE provides commercial support for btrfs and uses it as the default. That's pretty much as non-experimental as is gets.
  - mapgrep 6y ago
    In the past, when data integrity issues emerged, btrfs devs have stated that it is not ready for production. Has there been an announcement to the contrary? If btrfs is production ready, is this clearly stated somewhere? Solaris has defaulted to ZFS at least since version 11 first released eight years ago. Update - also it appears Suse enterprise uses btrfs for the root os filesystem but xfs for everything else including by default /home. To me, this seems telling? If it’s so solid why not use it for /home?
- deleted 6y ago
  [deleted]

curt15 6y ago

Fedora is proposing to default to btrfs for its next release: https://fedoraproject.org/wiki/Changes/BtrfsByDefault https://fedoraproject.org/wiki/Changes/BtrfsByDefault

throw0101a 6y ago
Contrast with Debian's warnings on the topic: * https://wiki.debian.org/Btrfs#Warnings https://wiki.debian.org/Btrfs#Warnings