VMware’s Founder Helped To Inspire WAFL

At VMworld yesterday, I got to meet with Mendel Rosenblum, one of VMware’s founders. I want to share the story of how he helped inspire WAFL.

In the early days of NetApp, when we first started developing our WAFL file system, we drew inspiration from three main file systems: FFS, Episode and LFS:

The Berkeley Fast File System (FFS) was written by Kirk McKusick. I had worked on FFS at two prior companies (MIPS and Auspex), so I was very familiar with it.

The Episode File System was developed by Transarc, which spun out of the Andrew File System (AFS) project at Carnegie Mellon. One of the architects of Episode was Mike Kazar, who joined NetApp when we acquired Spinnaker.

The Log-structured File System (LFS) was developed as part of John Ousterhout’s Sprite operating system project at Berkeley.

The graduate student who actually designed and implemented LFS was Mendel Rosenblum. It took me quite a few years to figure out that this guy whose work I admired 15 years ago was the same guy who started VMware. Imagine my surprise!

Given that a VMware founder helped inspire WAFL, it seems there’s a sort of poetic justice that so many VMware customers use it for their data.

Comments

Hey Dave. This is very interesting and a wonderful tribute to the great
minds of file systems. I enjoyed skimming through links you provided and
enjoyed the LFS one the most. I noticed, like WAFL, it discussed
consistency points/checkpoints for storing consecutive file systems and
their metadata on disk and was wondering if this was new to WAFL or if
it was WAFL's write allocation techniques which really set it apart in
the market. Thanks

-- Anonymous

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WAFL shares some ideas in common with each of these other file systems, but the implementation is different in many ways.

–Dave Hitz

[tipaza]

great WAFL "prior work" references, thanks for the history. btw, same references are mentionned by ZFS founders

[Ohad Rodeh]

Dave,
I have been following your blog for a while now; I find it very interesting.

A while ago I tried to add b-trees to WAFL and to improve its snapshot capabilities. The result was presented at the February 2007 Linux file-system workshop, see this link: http://www.cs.tau.ac.il/~ohadrode/papers/LinuxFS_Workshop.pdf

A journal paper is also due to appear. I am interested in your thoughts on the matter. Do these techniques solve a real problem?

Ohad.

[anonym]

Dave ,
Inspiring stuff on FS.Realy inspires new FS to build.

[Travis Roberts]

maybe he should sue you or netapp for using his inspiriation as the basis for your filesystem