file system deadlock - the whole story?

[Robert Watson]

On Wed, 19 Jul 2006, User Freebsd wrote:

> Also note that under FreeBSD 4.x, all three of these machines were pretty 
> much my more solid machines, with even more vServers running on them then 
> I'm able to run with 6.x ... once I got rid of using unionfs, stability 
> skyrocketed :(
>
> Hrmmmm ... but, your 'controller driver' comment ... that is one common 
> thing amongst all three servers ... they are all running the iir driver ... 
> not sure the *exact* controller, but pluto (older Dual-PIII) shows it as:

Yes, this was going to be my next question -- if you're seeing wedges under 
load and there's a common controller in use, maybe we're looking at a driver 
bug.  Bugs of those sort typically look a lot like what you describe: an I/O 
is "lost" and so eveything that depends on the I/O wedges waiting for it, 
leading to a lot of processes hanging around waiting for vnode locks, etc.

Robert N M Watson
Computer Laboratory
University of Cambridge