Re: [PATCH 1/8] pseries: phyp dump: Docmentation

On 10/01/2008, Nathan Lynch [off-list ref] wrote:

Mike Strosaker wrote:

quoted

At the risk of repeating what others have already said, the PHYP-assistance
method provides some advantages that the kexec method cannot:
 - Availability of the system for production use before the dump data is
collected.  As was mentioned before, some production systems may choose not
to operate with the limited memory initially available after the reboot,
but it sure is nice to provide the option.

I'm more concerned that this design encourages the user to resume a
workload *which is almost certainly known to result in a system crash*
before collection of crash data is complete.  Maybe the gamble will
pay off most of the time, but I wouldn't want to be working support
when it doesn't.

Workloads that cause crashes within hours of startup tend to be
weeded-out/discovered during pre-production test of the system
to be deployed. Since its pre-production test, dumps can be
taken in a leisurely manner. Heck, even a session at the
xmon prompt can be contemplated.

The problem is when the crash only reproduces after days or
weeks of uptime, on a production machine.  Since the machine
is in production, its got to be brought back up ASAP.  Since
its crashing only after days/weeks, the dump should have
plenty of time to complete.  (And if it crashes quickly after
that reboot ... well, support people always welcome ways
in which a bug can be reproduced more quickly/easily).

--linas