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ZFS On Linux Runs Into A Snag With Linux 5.0

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  • AndrewDB
    replied
    Originally posted by oiaohm View Post
    https://yarchive.net/comp/linux/kernel_fp.html
    This is when __kernel_fpu_begin and __kernel_fpu_end features were introduced into the Linux kernel.
    ...
    The reality here like it or not the ZFS On Linux are at fault.
    ...
    That was a very interesting comment, and I apologize for editing it. Just want to comment on two things.
    1) Nobody is really at fault here, it just so happens that the ZFS kernel driver code for x86 and x86_64 was using the decades old x87 FPU and so required access to the FPU registers directly. It's a software development accident. Things like that happen all the time. Unfortunately people on the LKML tend to get a little bit nervous quite often.
    2) Since ZOL also compiles for the arm, aarch64, ppc64 and ppc architectures, there is probably a solution or workaround that does not involve accessing the x87 registers directly. So yes, in the end the burden of fixing this will be on ZOL developers, but there is probably a simple solution, and the ZOL code will only improve from not messing with the (particularly finicky) x87 registers directly. So in the end ZFS on Linux users will benefit from this.

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  • WorBlux
    replied
    Originally posted by oiaohm View Post
    SIMD has to have the same protection switches as using FPU. Thank you intel for deciding to recycle some the less stable register copy operations in side their cpus..

    The Linux kernel has a crypto_shash that wraps over all you hardware acceleration for checksums. Really bad news to use a lot of the hardware accelerations you need patent licenses Guess what OIN has got those patents license for the Linux kernel. Wait for the other shoe to drop. The patent license that OIN aquired only cover you if your code is GPL.

    On hardware with proper checksum hardware accelerators ZFS on Linux not being GPL is going to be slow vs GPL file-systems in the Linux kernel doing checksums.

    This is one of the problems you hit when you go to freebsd from linux is that hardware accelerators no longer have drivers and it not possible to write a non GPL driver for them.
    Why wouldn't the use of accelerators be covered under the patent exaushtion doctrine? What patents exactly are we talking about?

    Leave a comment:


  • WorBlux
    replied
    Originally posted by k1e0x View Post

    OpenZFS is a fork and it's *not* a corporate filesystem project. They have ZERO involvement with Oracle. It's license is similar to MPL (are you reading this in Firefox, it's MPL too) and one could argue it's more permissive and free than Linux itself. (hence it's inclusion in FreeBSD, Mac OSX, even Microsoft Windows now. The only place it's "not allowed" is Linux.)

    My problem isn't the API change. I'm sure they will work that out. The issue is the emotional comments by Linux kernel dev's and the users.. whatever Sun's motivation. (and someone show me some proof they actually believed CDDL was not compatible, because it's was Debian that made that determination.) ..Whatever their motivation.. they are long since dead. Time to move on.

    IMO this is dumb. NIH and zealots a lot. You have two pieces of awesome totally open source technology Linux and ZFS, make them work together and put *actual* commercial storage (cough NetApp) out of business. Technology and solutions to problems should not be based on how you feel about Sun.
    Firefox doesn't require an out of tree module to function. For the CDDL code to be link-compatible with GPL 2+ code, you'd need a separate royalty-free perpetual patent grant to all GPL licensees, or be sure that all patents have expired. Not impossible, but without Oracle on board, it'd be 2033 at the earliest.

    The CDDL is at first glance, incompatible with the "without any other restriction" clause of the GPL. Nobody with deep pockets is going to risk distributing a compiled ZFS module for fear that a Linux rights-holder will be after them, either for a paycheck or for business/competition reasons.

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  • pgoetz
    replied
    Originally posted by pal666 View Post
    no, btrfs was started by one guy before he went to work for oracle. iirc he was working for suse.
    so what is stopping oracle from contributing zfs propely just as they "contributed" btrfs?
    Yeah, that's wrong too. Btrfs started at Oracle: https://www.linuxfoundation.org/blog...ason-on-btrfs/

    Leave a comment:


  • pgoetz
    replied
    Originally posted by pal666 View Post
    only zfs has such deficiency. btrfs can have multiple copies of data on one drive. and it has multiplie copies of metadata on one drive by default. btrfs is superior to zfs in any way possible
    This comment demonstrates you have no idea what you're talking about. A vdev can be a disk partition; so partition your disk into two vdevs and mirror them. Or you can just use the built in fs features:
    https://docs.oracle.com/cd/E19253-01...vpg/index.html

    In particular, disks are cheap, I never put anything, no matter how trivial, on a single disk without redundancy any more. The fact that you're talking about this raises questions. I guess maybe you're in Burundi, working with a budget of $2, or something?

    And of course you can use ZFS on a single disk, there's just no point in doing so. https://forums.freenas.org/index.php...ive-zfs.35515/

    From your comments it appears that you're a btrfs fan, and are using this in a professional situation? I'd be happy to switch to Btrfs, but can't find any storage admin willing to endorse such a thing. Everyone (but you) views Btrfs as too unstable for serious production use, and things like this don't help:

    https://www.phoronix.com/scan.php?pa...RAID-56-Is-Bad
    https://www.phoronix.com/scan.php?pa...-Not-All-Clear
    https://superuser.com/questions/1371...hile-balancing
    https://btrfs.wiki.kernel.org/index.php/RAID56
    https://www.reddit.com/r/btrfs/comme..._raid_56_bugs/
    https://news.ycombinator.com/item?id=16798157
    Last edited by pgoetz; 01-13-2019, 11:55 AM.

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  • Rallos Zek
    replied
    Originally posted by skeevy420 View Post

    Like the BSD kernel that Sony uses with their Playstation products? Sony is only the #1 in the world when it comes to game consoles and they use a non-gpl open source kernel.
    Is it Open Source still if you can see or inspect the code?

    Leave a comment:


  • Weasel
    replied
    Originally posted by oiaohm View Post
    SIMD has to have the same protection switches as using FPU.
    No it doesn't. Unless you refer to MMX but nobody really uses that. SSE is completely separate registers from the x87 FPU.

    Originally posted by oiaohm View Post
    Thank you intel for deciding to recycle some the less stable register copy operations in side their cpus..
    Again, plain wrong, nothing is recycled. And also floating point is not "unstable", it always gives the exact same result given the same state. However, you don't have to use floating point moves to move between SIMD registers (which is what copy operations are), so you are COMPLETELY wrong.

    btw, SIMD have many integer operations and I'm pretty sure it's what the checksum uses. The AES instructions also operate on SIMD registers but they are pure logical/integer instructions only.

    Leave a comment:


  • aht0
    replied
    Originally posted by pal666 View Post
    there is a dominating linux kernel. and there is a bunch of trolls doing helpless bla bla bla on forums. not very smart and not very reality-aware trolls
    Already know plenty of your opinions..
    "Deutschland, Deutschland, khm,. Linux, Linux über alles,
    über alles in der Welt.."

    I'll leave it to you to figure out the exact origins of the hymn above

    Server space, excepting web servers (intranet), is dominated by Windows servers (~60%+ - I am extrapolating it from analytical data applying to Netherlands, which is your average free democratic country, "as good as any other"), smart phone business dominated by Android.. will see if Google's Fuchsia would eat it out of the market or not in the future..

    If I was you, I'd get down from that high horse. Strong alternatives make also Linux stronger.
    Last edited by aht0; 01-12-2019, 10:11 AM.

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  • some_canuck
    replied
    we seem to have struck a nerve with pal the troll

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  • skeevy420
    replied
    Originally posted by pal666 View Post
    yes. non-gpl modules are bad for linux. just look at overwhelming success of non-gpl kernels
    Like the BSD kernel that Sony uses with their Playstation products? Sony is only the #1 in the world when it comes to game consoles and they use a non-gpl open source kernel.

    Leave a comment:

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