file system deadlock - the whole story?

[User Freebsd]

On Wed, 19 Jul 2006, Kostik Belousov wrote:

> On Wed, Jul 19, 2006 at 11:23:21AM -0300, User Freebsd wrote:
>> On Wed, 19 Jul 2006, Robert Watson wrote:
>>
>>>
>>> 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.
>>
>> 'k, but how do we debug *that*? :(  If it was one, I'd suspect hardware
>> ... but *three*, and only acting up *after* upgrading to FreeBSD 6.x, and
>> only acting up under load ...
>
> Obvious step would be to replace controller by some different kind.

Unfortunately, that one isn't an option ... these aren't local machines 
that I can easily swap hardware in :(

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
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