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I'm only a casual user of ZFS on Linux for personal storage projects, but I've spoken with people who rely very heavily on ZFS on Linux for their small business

I'm only a casual user of ZFS on Linux for personal storage projects, but I've spoken with people who rely very heavily on ZFS on Linux for their small businesses, and it's interesting to hear their perspectives on this. Essentially, because btrfs has failed to deliver on the next-gen filesystem front, ZFS on Linux is such a critical piece of technology that unless Red Hat has an answer soon for out-of-the-box ZFS on Linux, Canonical has a pretty staggering advantage. One theory is that Canonical has essentially forced Oracle to decide whether it wants to crack down on inclusion of CDDL-licensed code being shipped with Ubuntu's stock kernel, so Red Hat may be waiting to see if Oracle sweeps in or not before following suit. I'd be very surprised if RHEL (by observing the progression of Fedora development) continues to bet on btrfs, as I have yet to encounter anyone (including myself) who would ever trust btrfs over ZFS on Linux with anything of importance based on their experiences with the two - my experience is anecdotal, but ZFS has been just as reliable on *BSD as with any Linux distribution.

majormjr 9y ago
btrfs is getting dropped from future versions of RHEL so you can see what Red Hat thinks of the future of btrfs.
- user5994461 9y ago
  RedHat is betting on xfs.
- gribbly 9y ago
  Red Hat has never spent any real resources on btrfs, they've been all about XFS when it comes to enterprise needs.
  - cmurf 9y ago
    They employed one of the original Btrfs developers for the first half of its development, but not since 2012. I can't speak of their recruitment efforts, but it does seem all the Btrfs developers are happy at their respective companies; and the Red Hat file systems folks are happy working on what they're working on which is not Btrfs.
georgyo 9y ago
Oracle is not the one that could sue. There is nothing in the CDDL that prevents it being used else where. The GPL on the other hand is a strong copy left. If you link against GPL code, your code must also be licensed as GPL. This means the Linux copyright owners could sue the distributers of ZoL binaries, but Oracle could not. Oracle has the power to allow their ZFS code to be relicensed as GPL, removing this road block, but they have no incentive to do so.
- gribbly 9y ago
  As I understand it, the license incompability between GPL and CDDL is that CDDL adds a restriction regarding patents, and GPL does not allow for additional restrictions to be added. So to distribute CDDL licensed code is a breach of BOTH licenses as I see it, ignoring the 'patent peace' requirement of CDDL which would be the case if distributing it as GPL does not sound legal to me (IANAL). I can certainly understand why Linus has stated that no CDDL code will be mainlined (brought into the Linux kernel tree), it all seems very ambiguous.
  - greenhouse_gas 9y ago
    IANAL, but it (probably) depends on which license Canonical is using for the ZFS plugin. If they use CDDL, then I can't see how Oracle would have a case.
    - fnj 9y ago
      They can't legally use anything except CDDL. If anyone could just pick and choose to alter the licensing, there wouldn't be any point in having licences.
- lottin 9y ago
  According to the Software Freedom Conservancy ...redistributing a binary work incorporating CDDLv1'd and GPLv2'd copyrighted portions constitutes copyright infringement in both directions... [https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/ https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/] so it seems that Oracle could in fact sue.
scottLobster 9y ago
RedHat is apparently building something new called Stratis based on XFS, they're shooting for delivery within the next 1-2 years. Supposedly it'll be feature-equivalent to ZFS/Btrfs/LVM. http://www.phoronix.com/scan.php?page=news_item&px=Stratis-Red-Hat-Project http://www.phoronix.com/scan.php?page=news_item&px=Stratis-R...
- cmurf 9y ago
  The ZFS comment in the document [1] is time inspecific. It's got version 1.0 in 1st half of 2018 and the "rough ZFS feature parity" comment is not until version 3.0, which has no listed time frame. This is going to take lot of work, and not just for the stratis developers but for projects that need to manipulate it. It's asking for a lot of work for bootloader projects to support it, and [1] https://stratis-storage.github.io/StratisSoftwareDesign.pdf https://stratis-storage.github.io/StratisSoftwareDesign.pdf
  - X86BSD 9y ago
    Filesystems are HARD, see the plethora of FS's on Linux that are dead, dying, or horribly engineered. This seems like such a monumental waste of resources, time, and energy to chase ZFS, which itself is not a stationary target. ZFS is constantly developing new features. I think a lack of ZFS in Linux is hurting it. And that wound will only deepen over time.
    - gribbly 9y ago
      Well obviously Linux devs would love having ZFS in the kernel, Linus even half joked that he'd consider trying to relicense Linux to GPLv3 if it meant he could use ZFS and DTrace (this was back when Sun was considering GPLv3 as the license to use when going open source). But the problem remains, CDDL and GPL are likely incompatible, and Linus has said that no CDDL licensed code will be merged, most likely per advice from lawyers. So unless something drastically changes, ZFS is off the table, and thus work will continue on with alternatives, Stratis is one such alternative, bcachefs is another, and of course btrfs will not die just because Red Hat isn't supporting it anymore, as they barely did to begin with.
gribbly 9y ago
>One theory is that Canonical has essentially forced Oracle to decide whether it wants to crack down on inclusion of CDDL-licensed code being shipped with Ubuntu's stock kernel Huh? Are Canonical is shipping ZFS in their kernel now ? I thought they just distributed it as a separate module.
- ethbro 9y ago
  There was an article a bit ago on HN where the Free Software Conservancy (?) wrote that legally, shipping a precompiled binary kernel module is the same as having it in the kernel.
  - gribbly 9y ago
    But obviously Canonical's lawyers don't think shipping it separately is the same as shipping it in the kernel, because if they did they would not ship it separately to begin with.
    - ethbro 9y ago
      Granted. But Canonical's lawyers are not canonical. There's legal disagreement, and saying "Ubuntu did it" doesn't make those problems disappear. (Sadly)
      - gribbly 9y ago
        >>But Canonical's lawyers are not canonical. Hmm... not sure what you meant by this statement ?
        ethbro 9y ago
        "authorized; recognized; accepted" I.e. their opinion is not the only opinion on the matter.
      - FireBeyond 9y ago
        I haven't seen any legal opinion since Canonical's press release, which states that they consulted with counsel who believed that they were in compliance with both licenses. I -have- seen a lot of argument online, opinions and otherwise that disagree with this, but not anything from a lawyer - mainly "philosophical" or opining on the "intent" of the GPL, rather than "based on clauses x, y, and z, this is impermissible". Which is not to say, if something of an opinion exists in response to Canonical's release of ZFS, I would love to see it - a legal opinion, not armchair lawyering or opinionizing.
cmurf 9y ago
SUSE has succeeded in shipping atomic OS updates and rollbacks by default both for enterprise and community versions of Linux several years ago. Facebook is using it, and the usage is growing. [1] And there are any number of examples of production usage of Btrfs at scale if you go look for them. [2] And the good and bad are fairly well understood, it is in fact getting better and will continue to get better.[3] And Red Hat isn't waiting. [4] [1] https://www.spinics.net/lists/linux-btrfs/msg67885.html https://www.spinics.net/lists/linux-btrfs/msg67885.html [2] https://www.spinics.net/lists/linux-btrfs/msg67308.html https://www.spinics.net/lists/linux-btrfs/msg67308.html [3] https://www.spinics.net/lists/linux-btrfs/msg67940.html https://www.spinics.net/lists/linux-btrfs/msg67940.html [4] https://stratis-storage.github.io/StratisSoftwareDesign.pdf https://stratis-storage.github.io/StratisSoftwareDesign.pdf What you're going to find in storage is that there are multiple valid approaches, no clear one size fits all winner, and people will choose based on the tools they're familiar with, the company they trust, and their use case. I pick Btrfs over ZFS pretty much based on equivalent trust and better flexibility for my use case, but then I'm much more familiar with Btrfs tools and where the bodies are buried than I am with ZFS. I don't need to go around impugning other projects to justify what I use.
- petre 9y ago
  Aren't Synology NAS devices also using Brtfs?
  - leonroy 9y ago
    Yep, although they don't use Btrfs RAID but instead run it on top of LVM which provides the necessary RAID functionality.
    - hrez 9y ago
      Does LVM usage facilitates bitrot self-healing on btrfs part?
doublerebel 9y ago
I have bet on ZFS for years in both business and my most important personal information and it has never let me down, on Illumos or Linux. Snapshots, upgrades, sync, and data transfer are just too easy to even consider switching. And support and features have seen steady improvements over the last decade. No other filesystem has all of these properties.
usefulcat 9y ago
RHEL is not continuing to bet on btrfs; they are deprecating it: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/7.4_Release_Notes/chap-Red_Hat_Enterprise_Linux-7.4_Release_Notes-Deprecated_Functionality.html https://access.redhat.com/documentation/en-US/Red_Hat_Enterp...
- cyphar 9y ago
  As was explained in depth in the HN comments, Red Hat's decision to not provide enterprise support is based on the fact that they don't have the necessary engineers to backport and maintain one of the fastest moving pieces of code in Linux today. All of their btrfs engineers moved to Facebook, and they're still working on btrfs improvements. There are many decisions involved in deciding what to provide enterprise support for, and whether you like it or not, technical merit is only one of many factors. So Red Hat's decision was likely not entirely based on technical merit. SUSE still provides enterprise support for btrfs (like we've always done), and there's still plenty of work being done from various large contributors. [I work at SUSE.]
  - cmurf 9y ago
    $ git log --since=”2016-01-01” --pretty=format:”%an” --no-merges -- fs/btrfs | sort -u And then iterate for ext4 and xfs, and that comes to: 100 btrfs, 71 ext4, and 63 XFS contributors over those 18 months. They are all healthy ecofilesystems.
  - usefulcat 9y ago
    It sounds like you think you're disagreeing with me, but I'm not sure how that's possible given the near total lack of opinion in my post. In any case, the aspect of the parent comment that I was thinking of when I posted that was the part where the parent points out that Ubuntu has ZFS and how that could be a problem for RHEL. Yes RHEL offers a number of other FS options, but to my knowledge only ZFS and btrfs currently offer checksumming, which IMO is a big differentiator vs. more conventional filesystems.
    - 9y ago
fnj 9y ago
> One theory is that Canonical has essentially forced Oracle to decide whether it wants to crack down on inclusion of CDDL-licensed code being shipped with Ubuntu's stock kernel, so Red Hat may be waiting to see if Oracle sweeps in or not before following suit. That is not a "theory" that anyone who understands the basics of the licenses adheres to. The possible threat is that linux' GPL could attack ZFS; not the other way round. There is nothing in the CDDL in the way of using ZFS in linux.

majormjr 9y ago

btrfs is getting dropped from future versions of RHEL so you can see what Red Hat thinks of the future of btrfs.

user5994461 9y ago
RedHat is betting on xfs.
gribbly 9y ago
Red Hat has never spent any real resources on btrfs, they've been all about XFS when it comes to enterprise needs.
- cmurf 9y ago
  They employed one of the original Btrfs developers for the first half of its development, but not since 2012. I can't speak of their recruitment efforts, but it does seem all the Btrfs developers are happy at their respective companies; and the Red Hat file systems folks are happy working on what they're working on which is not Btrfs.

georgyo 9y ago

Oracle is not the one that could sue. There is nothing in the CDDL that prevents it being used else where. The GPL on the other hand is a strong copy left. If you link against GPL code, your code must also be licensed as GPL. This means the Linux copyright owners could sue the distributers of ZoL binaries, but Oracle could not. Oracle has the power to allow their ZFS code to be relicensed as GPL, removing this road block, but they have no incentive to do so.

gribbly 9y ago
As I understand it, the license incompability between GPL and CDDL is that CDDL adds a restriction regarding patents, and GPL does not allow for additional restrictions to be added. So to distribute CDDL licensed code is a breach of BOTH licenses as I see it, ignoring the 'patent peace' requirement of CDDL which would be the case if distributing it as GPL does not sound legal to me (IANAL). I can certainly understand why Linus has stated that no CDDL code will be mainlined (brought into the Linux kernel tree), it all seems very ambiguous.
- greenhouse_gas 9y ago
  IANAL, but it (probably) depends on which license Canonical is using for the ZFS plugin. If they use CDDL, then I can't see how Oracle would have a case.
  - fnj 9y ago
    They can't legally use anything except CDDL. If anyone could just pick and choose to alter the licensing, there wouldn't be any point in having licences.
lottin 9y ago
According to the Software Freedom Conservancy ...redistributing a binary work incorporating CDDLv1'd and GPLv2'd copyrighted portions constitutes copyright infringement in both directions... [https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/ https://sfconservancy.org/blog/2016/feb/25/zfs-and-linux/] so it seems that Oracle could in fact sue.

scottLobster 9y ago

RedHat is apparently building something new called Stratis based on XFS, they're shooting for delivery within the next 1-2 years. Supposedly it'll be feature-equivalent to ZFS/Btrfs/LVM. http://www.phoronix.com/scan.php?page=news_item&px=Stratis-Red-Hat-Project http://www.phoronix.com/scan.php?page=news_item&px=Stratis-R...

cmurf 9y ago
The ZFS comment in the document [1] is time inspecific. It's got version 1.0 in 1st half of 2018 and the "rough ZFS feature parity" comment is not until version 3.0, which has no listed time frame. This is going to take lot of work, and not just for the stratis developers but for projects that need to manipulate it. It's asking for a lot of work for bootloader projects to support it, and [1] https://stratis-storage.github.io/StratisSoftwareDesign.pdf https://stratis-storage.github.io/StratisSoftwareDesign.pdf
- X86BSD 9y ago
  Filesystems are HARD, see the plethora of FS's on Linux that are dead, dying, or horribly engineered. This seems like such a monumental waste of resources, time, and energy to chase ZFS, which itself is not a stationary target. ZFS is constantly developing new features. I think a lack of ZFS in Linux is hurting it. And that wound will only deepen over time.
  - gribbly 9y ago
    Well obviously Linux devs would love having ZFS in the kernel, Linus even half joked that he'd consider trying to relicense Linux to GPLv3 if it meant he could use ZFS and DTrace (this was back when Sun was considering GPLv3 as the license to use when going open source). But the problem remains, CDDL and GPL are likely incompatible, and Linus has said that no CDDL licensed code will be merged, most likely per advice from lawyers. So unless something drastically changes, ZFS is off the table, and thus work will continue on with alternatives, Stratis is one such alternative, bcachefs is another, and of course btrfs will not die just because Red Hat isn't supporting it anymore, as they barely did to begin with.

gribbly 9y ago

>One theory is that Canonical has essentially forced Oracle to decide whether it wants to crack down on inclusion of CDDL-licensed code being shipped with Ubuntu's stock kernel Huh? Are Canonical is shipping ZFS in their kernel now ? I thought they just distributed it as a separate module.

ethbro 9y ago
There was an article a bit ago on HN where the Free Software Conservancy (?) wrote that legally, shipping a precompiled binary kernel module is the same as having it in the kernel.
- gribbly 9y ago
  But obviously Canonical's lawyers don't think shipping it separately is the same as shipping it in the kernel, because if they did they would not ship it separately to begin with.
  - ethbro 9y ago
    Granted. But Canonical's lawyers are not canonical. There's legal disagreement, and saying "Ubuntu did it" doesn't make those problems disappear. (Sadly)
    - gribbly 9y ago
      >>But Canonical's lawyers are not canonical. Hmm... not sure what you meant by this statement ?
      - ethbro 9y ago
        "authorized; recognized; accepted" I.e. their opinion is not the only opinion on the matter.
    - FireBeyond 9y ago
      I haven't seen any legal opinion since Canonical's press release, which states that they consulted with counsel who believed that they were in compliance with both licenses. I -have- seen a lot of argument online, opinions and otherwise that disagree with this, but not anything from a lawyer - mainly "philosophical" or opining on the "intent" of the GPL, rather than "based on clauses x, y, and z, this is impermissible". Which is not to say, if something of an opinion exists in response to Canonical's release of ZFS, I would love to see it - a legal opinion, not armchair lawyering or opinionizing.

cmurf 9y ago

SUSE has succeeded in shipping atomic OS updates and rollbacks by default both for enterprise and community versions of Linux several years ago. Facebook is using it, and the usage is growing. [1] And there are any number of examples of production usage of Btrfs at scale if you go look for them. [2] And the good and bad are fairly well understood, it is in fact getting better and will continue to get better.[3] And Red Hat isn't waiting. [4] [1] https://www.spinics.net/lists/linux-btrfs/msg67885.html https://www.spinics.net/lists/linux-btrfs/msg67885.html [2] https://www.spinics.net/lists/linux-btrfs/msg67308.html https://www.spinics.net/lists/linux-btrfs/msg67308.html [3] https://www.spinics.net/lists/linux-btrfs/msg67940.html https://www.spinics.net/lists/linux-btrfs/msg67940.html [4] https://stratis-storage.github.io/StratisSoftwareDesign.pdf https://stratis-storage.github.io/StratisSoftwareDesign.pdf What you're going to find in storage is that there are multiple valid approaches, no clear one size fits all winner, and people will choose based on the tools they're familiar with, the company they trust, and their use case. I pick Btrfs over ZFS pretty much based on equivalent trust and better flexibility for my use case, but then I'm much more familiar with Btrfs tools and where the bodies are buried than I am with ZFS. I don't need to go around impugning other projects to justify what I use.

petre 9y ago
Aren't Synology NAS devices also using Brtfs?
- leonroy 9y ago
  Yep, although they don't use Btrfs RAID but instead run it on top of LVM which provides the necessary RAID functionality.
  - hrez 9y ago
    Does LVM usage facilitates bitrot self-healing on btrfs part?

doublerebel 9y ago

I have bet on ZFS for years in both business and my most important personal information and it has never let me down, on Illumos or Linux. Snapshots, upgrades, sync, and data transfer are just too easy to even consider switching. And support and features have seen steady improvements over the last decade. No other filesystem has all of these properties.

usefulcat 9y ago

RHEL is not continuing to bet on btrfs; they are deprecating it: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/7.4_Release_Notes/chap-Red_Hat_Enterprise_Linux-7.4_Release_Notes-Deprecated_Functionality.html https://access.redhat.com/documentation/en-US/Red_Hat_Enterp...

cyphar 9y ago
As was explained in depth in the HN comments, Red Hat's decision to not provide enterprise support is based on the fact that they don't have the necessary engineers to backport and maintain one of the fastest moving pieces of code in Linux today. All of their btrfs engineers moved to Facebook, and they're still working on btrfs improvements. There are many decisions involved in deciding what to provide enterprise support for, and whether you like it or not, technical merit is only one of many factors. So Red Hat's decision was likely not entirely based on technical merit. SUSE still provides enterprise support for btrfs (like we've always done), and there's still plenty of work being done from various large contributors. [I work at SUSE.]
- cmurf 9y ago
  $ git log --since=”2016-01-01” --pretty=format:”%an” --no-merges -- fs/btrfs | sort -u And then iterate for ext4 and xfs, and that comes to: 100 btrfs, 71 ext4, and 63 XFS contributors over those 18 months. They are all healthy ecofilesystems.
- usefulcat 9y ago
  It sounds like you think you're disagreeing with me, but I'm not sure how that's possible given the near total lack of opinion in my post. In any case, the aspect of the parent comment that I was thinking of when I posted that was the part where the parent points out that Ubuntu has ZFS and how that could be a problem for RHEL. Yes RHEL offers a number of other FS options, but to my knowledge only ZFS and btrfs currently offer checksumming, which IMO is a big differentiator vs. more conventional filesystems.
  - 9y ago

fnj 9y ago

> One theory is that Canonical has essentially forced Oracle to decide whether it wants to crack down on inclusion of CDDL-licensed code being shipped with Ubuntu's stock kernel, so Red Hat may be waiting to see if Oracle sweeps in or not before following suit. That is not a "theory" that anyone who understands the basics of the licenses adheres to. The possible threat is that linux' GPL could attack ZFS; not the other way round. There is nothing in the CDDL in the way of using ZFS in linux.