Linked by Thom Holwerda on Tue 17th Sep 2013 22:04 UTC, submitted by garyd
General Development

ZFS is the world's most advanced filesystem, in active development for over a decade. Recent development has continued in the open, and OpenZFS is the new formal name for this open community of developers, users, and companies improving, using, and building on ZFS. Founded by members of the Linux, FreeBSD, Mac OS X, and illumos communities, including Matt Ahrens, one of the two original authors of ZFS, the OpenZFS community brings together over a hundred software developers from these platforms.

ZFS plays a major role in Solaris, of course, but beyond that, has it found other major homes? In fact, now that we're at it, how is Solaris doing anyway?

Thread beginning with comment 572490
To view parent comment, click here.
To read all comments associated with this story, please click here.
RE[7]: Comment by porcel
by pfgbsd on Thu 19th Sep 2013 09:48 UTC in reply to "RE[6]: Comment by porcel"
pfgbsd
Member since:
2011-03-12

Regarding SmartOS's use of KVM with the Illumos kernel, since the KVM modules would be linked against the kernel, and more specifically, linked against a public and well documented external API that is provided specifically for third parties to build and distribute kernel modules and drivers (Since Illumos has presumably kept the stable driver interfaces of Solaris), wouldn't it be a non-violation to port GPL kernels to Illumos? It'd be hard to say Illumos is a derived work of KVM if KVM links against public interfaces.


I am pretty sure the port is/was very invasive. It is not really a matter of KVM being a derivative work of Linux or not, KVM itself is GPLd so linking it to a non-free kernel would be a license violation.

OTOH, ZFS is in no way derivative work of the Linux kernel as it originated in another OS and, as you say, the porters are just linking against public interfaces.

Reply Parent Score: 1

RE[8]: Comment by porcel
by Drumhellar on Thu 19th Sep 2013 18:11 in reply to "RE[7]: Comment by porcel"
Drumhellar Member since:
2005-07-12

KVM for Illumos module doesn't use the deep hooks that the Linux system has (Which are marked as GPL-only)

The port didn't mod the Illumos kernel at all - all the changes live in the KVM module, which is also maintained separately from the Illumos kernel.

From an excellent article on it:
http://lwn.net/Articles/459754/

Of course some questions arose about the license: Joyent has copied the GPL-ed KVM code from Linux, while the illumos kernel uses the CDDL (Common Development and Distribution License). However, according to Cantrill this doesn't pose any problems. On his blog he answers a question from a reader about the issue:
Our KVM port remains GPL and its own work (and lives in its own repo) - the illumos kernel is CDDL but is in no way a derived work of our KVM port.

And on Hacker News he clarifies that their KVM port doesn't use the hooks that Linux KVM has into the Linux kernel (which are marked as EXPORT_SYMBOL_GPL in the Linux kernel): "Actually, our port does not use these hooks – there were zero mods to the illumos kernel to support KVM per se." So, although there seem to be some questions about the legality of the KVM module in illumos, the developers are fairly confident that the problems don't apply because the illumos kernel (CDDL-licensed) is not a derived work of the illumos KVM module (GPL-licensed).


You clearly don't know what you're talking about. Linux has a mix of public and private interfaces - private interfaces are marked as GPL only, Linus specifically says that linking against the public system call interfaces doesn't make your user space software a derived work of the kernel - It's not an exception, just a statement of fact.

Public and stable kernel module interfaces (Which Illumos is full of) would clearly fall under the "System Library" exception of the GPL. Either way, it's generally okay to write GPL code and link it against a non-free library. (see http://www.gnu.org/licenses/gpl-faq.html#FSWithNFLibs)
The FSF even grudgingly admits that.

Reply Parent Score: 4

RE[9]: Comment by porcel
by pfgbsd on Thu 19th Sep 2013 18:36 in reply to "RE[8]: Comment by porcel"
pfgbsd Member since:
2011-03-12

KVM for Illumos module doesn't use the deep hooks that the Linux system has (Which are marked as GPL-only)

...

You clearly don't know what you're talking about. Linux has a mix of public and private interfaces - private interfaces are marked as GPL only, Linus specifically says that linking against the public system call interfaces doesn't make your user space software a derived work of the kernel - It's not an exception, just a statement of fact.



TBH, I honestly don't care what linux consider private or public; the license doesn't mention any different between them so such considerations usually have little legal weight.

The more interesting question would be how this applies to ZFS. The ZFS on Linux site carries an informative link in their FAQ:

http://zfsonlinux.org/faq.html#WhatAboutTheLicensingIssue

The combination of them causes problems because it prevents using pieces of code exclusively available under one license with pieces of code exclusively available under the other in the same binary. In the case of the kernel, this prevents us from distributing ZFS as part of the kernel binary. However, there is nothing in either license that prevents distributing it in the form of a binary module or in the form of source code.

Reply Parent Score: 2