Comment 38 for bug 336652

I have had a very similar problem to this. I still have it often, but not as
much from when I changed from EXT3 to ReiserFS. For the Scheduler, I've been
using BFQ or V(R) thats included in the Zen Patchset. I have tried the stock
kernel, and same problem exists, however I can't remember which scheduler I
used at that point, I believe Deadline.
Most of the IOWait I get comes when either I'm copying files to the local
drives, or using multiple VM's (generally Windows as thats what is needed for
work). I'm willing to try about anything to get this fixed. It's a little
better since I switched FS's on my VM Drive, but still isn't totally fixed.