Comment 13 for bug 986654

This issue has been isolated down to the "udev" package.

Using "udev 175-0ubuntu6" the disk I/O is fine
Using "udev 175-0ubuntu9" the intensive disk bashing test fails.

The test has been repeated now a few times of starting from a fesh installation of the 2012.03.27 ISO, verifying things work properly, then making only the one package upgrade change, and then verifying that the disk test fails.

doug@test-smy:~/temp-kernel$ diff b3_pkg.txt b3_udev.txt
390c390
< ii udev 175-0ubuntu6 rule-based device node and kernel event manager
---
> ii udev 175-0ubuntu9 rule-based device node and kernel event manager

The next step will be to attempt to isolate the exact change within that package.