Serious I/O problems (bad performance and live-lock)

[Daniel Eriksson]

Scott Long wrote:

> Ok, next test would be to turn off mpsafevm.  This is just a simple
> guess, though, but and changes in the behaviour would be very
> interesting to note.

With debug.mpsafevfs="0" and debug.mpsafevm="0" it doesn't seem like I can
force the machine into live-lock. No matter how long I let 'dd' run I can
still abort it with CTRL-C easily. However, after a few minutes the machine
becomes mostly useless because it takes 30-60 seconds to execute simple
commands such as ps or ls.

According to 'top', the dd process spend most of its time in "wdrain" state.

/Daniel Eriksson