Big problems with 7.1 locking up :-(

[Robert Watson]

On Thu, 15 Jan 2009, Pete French wrote:

> Just an update on this - I tried the various kernels, but now the machine is 
> not locking up at all. As I havent actually chnaged anything then this does 
> not make me as happy as you might expect. I don;t know what to do now - I 
> daare not upgrade the machines to an OS that I know locks, but if I cant 
> make it lock then it is impossible to get any useful debugging info out of. 
> maybe waiting for 7.2 is the best move...

Well, one slightly pessimistic (or realistic) view says that all software 
contains bugs, it's just a question of whether or not your workload and 
environment trigger those bugs in a noticeable way.

Given the inconsistency of the symptoms, I wouldn't preclude something 
environmental: could it be that it was the bottom, or more likely, top box in 
a rack and that your air conditioning isn't quite as effective there when the 
outside temperature is above/below some threshold?  Alternatively, could it be 
that the workload changed very slightly -- you're doing less DNS queries, or 
the network latency to the DNS server changed?

Certainly, whoever gave the advise on checking BIOS revisions is right: you 
can spend a lot of time tracking down a bug to realize that one box has a 
slightly different BIOS rev and therefore does/doesn't suffer from an obscure 
SMI bug.

In any case, if it starts to reproduceably recur, send out mail and we can see 
if we can track it down some more.  BTW, did you establish if the version of 
iLo you have has a remote NMI?  I seem to recall that some do, and being able 
to deliver an NMI is really quite valuable.

Robert N M Watson
Computer Laboratory
University of Cambridge