[cryptonector]

The NetApp lawsuit. Apple wanted indemnification, and Sun/Oracle did not want to indemnify Apple.

At the time that NetApp filed its lawsuit I blogged about how ZFS was a straightforward evolution of BSD 4.4's log structured filesystem. I didn't know that to be the case historically, that is, I didn't know if Bonwick was inspired by LFS, but I showed how almost in every way ZFS was a simple evolution of LFS. I showed my blog to Jeff to see how he felt about it, and he didn't say much but he did acknowledge it. The point of that blog was to show that there was prior art and that NetApp's lawsuit was worthless. I pointed it out to Sun's general counsel, too.

[tw04]

While I was disappointed that NetApp sued, the ZFS team literally referenced NetApp and WAFL multiple times in their presenations IIRC. They were kind of begging to be sued.

Also, according to NetApp, "Sun started it".

https://www.networkcomputing.com/data-center-networking/neta...

[bcantrill]

No, the ZFS team did not "literally reference NetApp and WAFL" in their presentations and no, Sun did not "start it" -- NetApp initiated the litigation (though Sun absolutely countersued), and NetApp were well on their way to losing not only their case but also their WAFL patents when Oracle acquired Sun. Despite having inherited a winning case, Oracle chose to allow the suit to be dismissed[0]; terms of the settlement were undisclosed.

[0] https://www.theregister.com/2010/09/09/oracle_netapp_zfs_dis...

[tw04]

We can agree to disagree.

Your own link states that Sun approached NetApp about patents 18 months prior to the lawsuit being filed (to be clear that was Storagetek before Sun acquired them):

>The suit was filed in September 2007, in Texas, three years ago, but the spat between the two started 18 months before that, according to NetApp, when Sun's lawyers contacted NetApp saying its products violated Sun patents, and requesting licensing agreements and royalties for the technologies concerned.

And there was a copy of the original email from the lawyer which I sadly did not save a copy of, as referenced here:

https://ntptest.typepad.com/dave/2007/09/sun-patent-team.htm...

As for the presentation, I can't find it at the moment but will keep looking because I do remember it. That being said, a blog post from Val at the time specifically mentions NetApp, WAFL, how the team thought it was cool and decided to build your own:

https://web.archive.org/web/20051231160415/http://blogs.sun....

And the original paper on ZFS that appears to have been scrubbed from the internet mentions WAFL repeatedly (and you were a co-author so I'm not sure why you're saying you didn't reference NetApp or WAFL):

https://ntptest.typepad.com/dave/2007/09/netapp-sues-sun.htm...

https://www.academia.edu/20291242/Zfs_overview

>The file system that has come closest to our design principles, other than ZFS itself,is WAFL[8],the file system used internally by Network Appliance’s NFS server appliances.

[throw0101b]

> And the original paper on ZFS that appears to have been scrubbed from the internet mentions WAFL repeatedly (and you were a co-author so I'm not sure why you're saying you didn't reference NetApp or WAFL):

Cantrill was not involved in ZFS, and was not a co-author. Cantrill was involved with DTrace:

* https://www.usenix.org/conference/2004-usenix-annual-technic...

* https://www.cs.princeton.edu/courses/archive/fall05/cos518/p...

And the ZFS paper has hardly been scrubbed given it is widely cited:

* https://www.cs.hmc.edu/~rhodes/cs134/readings/The%20Zettabyt...

And the fact that the ZFS paper cites WAFL is hardly an indication of anything, given that NetApp's patent cites a whole bunch of other patents:

* https://patents.google.com/patent/US5819292#patentCitations

Heck, some of the cited patents were Sun's.

* https://en.wikipedia.org/wiki/NetApp#Legal_dispute_with_Sun_...

[cryptonector]

> The file system that has come closest to our design principles, other than ZFS itself,is WAFL[8],the file system used internally by Network Appliance’s NFS server appliances.

That was unnecessary, but that does not betray even the slightest risk of violating NetApp's patents. It just brings attention.

Also, it's not true! The BSD 4.4 log-structured filesystem is such a close analog to ZFS that I think it's clear that it "has come closest to our design principles". I guess Bonwick et. al. were not really aware of LFS. Sad.

LFS had:

  - "write anywhere"
  - "inode file"
  - copy on write

LFS did not have:

  - checksumming
  - snapshots and cloning
  - volume management

And the free space management story on LFS was incomplete.

So ZFS can be seen as adding to LFS these things:

  - checksumming
  - birth transaction IDs
  - snapshots, cloning, and later dedup
  - proper free space management
  - volume management, vdevs, raidz

I'm not familiar enough with WAFL to say how much overlap there is with WAFL, but I know that LFS long predates WAFL and ZFS. LFS was prior art! Plus there was lots of literature on copy-on-write b-trees and such in the 80s, so there was lots of prior art in that space.

Even content-addressed storage (CAS) (which ZFS isn't quite) had prior art.

[throw0101b]

> I guess Bonwick et. al. were not really aware of LFS. Sad.

They were:

> [16] Mendel Rosenblum and John K. Ousterhout. The design and implementation of a log-structured file system. ACM Transactions on Computer Systems, 10(1):26–52, 1992.

> [17] Margo Seltzer, Keith Bostic, Marshall K. McKusick, and Carl Staelin. An implementation of a log-structured file system for UNIX. In Proceedings of the 1993 USENIX Winter Technical Conference, 1993.

* https://www.cs.hmc.edu/~rhodes/cs134/readings/The%20Zettabyt...

[ahl]

Seems specious. Patents don't preclude one from overtly trying to compete; they protect specific mechanisms. In this case either ZFS didn't use the same mechanisms or the mechanisms themselves were found to have prior art.

[tw04]

Whether the claims were valid or not I guess we'll never know given Oracle and NetApp decided to settle.

What I DO knows is that if the non-infringement were as open and shut as you and Bryan are suggesting, Apple probably wouldn't have scrapped years of effort and likely millions in R&D for no reason. It's not like they couldn't afford some lawyers to defend a frivelous lawsuit...

[ahl]

Maybe! Bryan and I were pretty close to the case and to the implementation of ZFS. But maybe Apple did detect some smoking gun of which somehow we were unaware. I (still) think Jonathan’s preannouncement was the catalyst for Apple changing direction.

[tw04]

I will just say I can’t thank both of you enough. I cut my teeth on zfs and it was a pillar of the rest of my career.

It’s a constant reminder to me of the value of giving that college kid free access to your code so they can become the next expert doing something creative you never thought of.

[cryptonector]

There was lots of prior art from the 80s for "write anywhere", which is a generally a consequence of copy-on-write on-disk formats. The write-anywhere thing is not really what's interesting, but, rather, not having to commit to some number of inodes at newfs time. Sun talking about NetApp makes sense given that they were the competition.

We don't know exactly what happened with Apple and Sun, but there were lots of indicia that Apple wanted indemnification and Sun was unwilling to go there. Why Apple really insisted on that, I don't know -- I think they should have been able to do the prior art search and know that NetApp probably wouldn't win their lawsuits, but hey, lawsuits are a somewhat random function and I guess Apple didn't want NetApp holding them by the short ones. DTrace they could remove, but removing ZFS once they were reliant on it would be much much harder.

[cryptonector]

Ok? So what?