[OpenAFS] AFS and PhotoShop interaction?

Mike Polek mike@pictage.com
Wed, 20 Dec 2006 20:01:34 -0800

As a follow-up to the follow up, I'd like to put in a little testimonial.

This issue is something that has plagued us for a long time... and of
course things got worse during the busy season, right when we needed
things to go faster. I had assumed for a while that my users were just
hitting the fileserver hard, but when I finally delved into the
problem, I discovered the issue with Photoshop doing file accesses
that proved inefficient in conjunction with the AFS Windows client.

After submitting a bug report and a little bit of back and forth
to get a handle on what the problem really was, Jeffrey did some
research and uncovered the underlying issue. From this, we were
able to come up with a short-term workaround for the really problematic
places, and we chose to fund the development effort to fix the
underlying issue so that all the places where we had some
large directory fan-out wouldn't continue to slow us down.
(We weren't going to build workarounds for every directory.)

In less than a week, Jeffrey had a build ready for us to test, and
the results were exactly what we needed. Where before images
had been loading at speeds of over 5 seconds per image (even if
the images were in the cache!), now they were loading in a second
or two. We didn't know whether to laugh or cry.... (no more
coffee breaks waiting for Photoshop to load 20 images).

I've thanked Jeffrey personally, and I'd also like to do so publicly.
Getting the work done was a graceful process, and well worth my
time and the funds allocated to the project. It makes our job so
much lighter when we stop getting complaints, and instead we get
comments like, "What did you do? AFS is so much faster!"

We're in the process of distributing the build, and I'm sure I'll
have more to say when we get feedback from our users.

As always, we appreciate all who contribute to Open Source initiatives
in any way... whether it's coding, testing, writing up bug reports
so the product can be improved, or funding. Everyone benefits.
Special thanks to the gatekeepers who continue to maintain and
improve OpenAFS as a truly outstanding product.

Michael Polek
Director of System Operations
1580 Francisco Street, Suite 101
Torrance, CA 90501

Jeffrey Altman wrote:
> As a follow-up, I have spent the last few weeks working on this issue.
> Indeed, Photoshop's behavior is hideous but that doesn't mean that
> OpenAFS couldn't be more efficient.


> With this change, the performance of Photoshop on directory trees with
> large numbers of entries becomes more than reasonable.  250MB JPGs open
> in about two seconds of clock time when stored in a three directory deep
> tree.  At the same time AFS client service CPU utilization remains in
> the single digits instead of using 99% of a single processor.


> I wish to thank Pictage for funding this research and development that
> the entire community in going to benefit from.
> These changes will appear in 1.5.13.
> Jeffrey Altman
> Secure Endpoints Inc.