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From: Theodore Tso <>
Newsgroups: fa.linux.kernel
Subject: Re: ZFS with Linux: An Open Plea
Date: Tue, 17 Apr 2007 17:51:45 UTC
Message-ID: <>

On Tue, Apr 17, 2007 at 12:22:19PM -0400, Daniel Hazelton wrote:
> Nope. You've just ignored it when it was explained *why* the existing ZFS code
> cannot be simply be ported to Linux. If you really need ZFS on linux, might I
> suggest that you port the code on your own and maintain whatever patches are
> needed to use it? As it stands ZFS *might* show up in Linux as a from-scratch
> implementation, although I stress the "might" because there are patents
> involved.

Given that Sun has reportedly filed a huge number of patents covering
ZFS and has refused to make them available for anything other than
Solaris --- and there are senior Sun programmers who have on record
stated that one of the reasons why Sun picked the CDDL was precisely
because it was incompatible with GPL and Sun fears Linux ---- I
wouldn't bet on Sun being willing to making a patent license available
to a hypothetical alternate implementation of the ZFS format for

Again, this is is Sun's fault, and it's because they fear Linux, and
it may have something to do with the fact that the vast majority of
their Opteron boxes get Linux installed instead of Solaris.  The
bottom line is that people who would like ZFS need to understand that
the code is Copyright by Sun, and there are almost certainly patents
owned by Sun, and if they choose licenses that are explicitly designed
to be incompatible with Linux, we should respect Sun's deep-seated
fear of Linux, and we can continue trying to innovate around better
filesystem and LVM storage technologies, as opposed to trying to chase
the ZFS tail lights.

Of course, this is all open source.  If someone wants to work on
reimplementing ZFS from scratch, either in userspace or in the kernel,
certainly the Linux community won't stop them.  Given the patent
issues Linus might not feel comfortable including it in the mainline
sources without a promise from Sun that they won't sue the pants off
of him and The Linux Foundation, but again, that's Sun's decision, and
no one else can help you there.

						- Ted

From: Theodore Tso <>
Newsgroups: fa.linux.kernel
Subject: Re: Why ask Sun for ZFS while we have ReiserFS4 !?
Date: Sun, 29 Apr 2007 23:42:34 UTC
Message-ID: <>

On Mon, Apr 30, 2007 at 02:18:19AM +0800, Andrew Wang wrote:
> ZFS has some nice features, but ReiserFS4 also is a
> good file system.
> Why do we want Sun to release ZFS under GPL, while
> ReiserFS4 is already available under GPL!?

The people who want ZFS have in mind certain features, such as the
ability to scale to very large sizes, and ease of use when
administering filesystems that span multiple disks (ZFS subsumes the
device-mapper/RAID layer in Solaris, so they get certain performance
benefits and they are able to make it simpler to set up a filesystem
that spans multiple disks with a single command --- the flip side is
that they are violating an relatively well understood abstraction
boundary, for better or for worse).

The claimed advantages of Reiser4 don't overlap much (if at all) with
the claimed advantages of ZFS.

> I think for those who ask/beg Sun to release ZFS under
> GPL should do the work to get ReiserFS4 to Linux!

Most of the people who have been cheerleading for either ZFS or
Reiser4 don't seem to have the necessary technical skills, alas.

					- Ted

From: Theodore Tso <>
Newsgroups: fa.linux.kernel
Subject: Re: Why ask Sun for ZFS while we have ReiserFS4 !?
Date: Tue, 01 May 2007 16:17:33 UTC
Message-ID: <fa.BQpYR0xLqRqzBL4yYGz7/>

On Tue, May 01, 2007 at 09:17:14PM +0800, Xu CanHao wrote:
> Reiser4 may lack some core function, but ZFS on Solaris is as
> functional as ext3 on Linux(or even more). So compare Reiser4 with
> ZFS may be inappropriate.

Functional, but it's a new filesystem with not as much time-tested
experience in the field.  Many Solaris system administrators are
electing to wait rather than immediately press it into service for
critical servers, electing to use Solaris's UFS instead.  I've heard a
few problems with ZFS recovering from data corruption, but not enough
to know whether it is a general trend (not that I track that kind of
stuff).  As a rule, enterprise system administrators that run PO
servers for thousands of users as a time are extremely conservative,
and for good reason.

Of course, there's a big difference between those folks and people
using ZFS for their own personal development.

						- Ted

From: Theodore Tso <>
Newsgroups: fa.linux.kernel
Subject: Re: ZFS with Linux: An Open Plea
Date: Wed, 02 May 2007 20:54:13 UTC
Message-ID: <fa.BU87a3/>

On Wed, May 02, 2007 at 04:42:47PM +0100, Alan Cox wrote:
> > I'm just found something new in filtered folder by "ZFS" word in RSS feed
> > from and on firs look it may be some continuation of this
> > thread:
> >
> >
> >
> > I'm not check completly this .. so don't beat me if it is not true :)
> Useful if accurate as the GPLv2 and Sun origin means you are clear for
> any patents Sun used in that code but maybe not for any in the pure CDDL
> bits. Definitely positive.

Well, except remember that they only made sources available so that
GRUB could boot OpenSolaris.  Grub only requires read-only access to
the filesystem, and what was made available under GPLv2 was only a
distinct subset of the full ZFS sources.

						- Ted

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