We now have the ComponentFail test in CTS. Thanks Lars for getting it
going!
And, in the process, it's showing up some kinds of problems that we
hadn't been looking for before. A couple examples of such problems can
be found here:
http://old.linux-foundation.org/developer_bugzilla/show_bug.cgi?id=1762
http://old.linux-foundation.org/developer_bugzilla/show_bug.cgi?id=1732
The question that comes up is this:
For problems that should "never" happen like death of one of our
core/key processes, is an immediate reboot of the machine the right
recovery technique?
The advantages of such a choice include:
It is fast
It will invoke recovery paths that we exercise a lot in testing
It is MUCH simpler than trying to recover from all these cases,
therefore almost certainly more reliable
The disadvantages of such a choice include:
It is crude, and very annoying
It probably shouldn't be invoked for single-node clusters (?)
It could be criticized as being lazy
It shouldn't be invoked if there is another simple and correct method
Continual rebooting becomes a possibility...
We do not have a policy of doing this throughout the project, what we
have is a few places where we do it.
I propose that we should consider making a uniform policy decision for
the project - and specifically decide to use ungraceful reboots as our
recovery method for "key" processes dying (for example: CCM, heartbeat,
CIB, CRM). It should work for those cases where people don't configure
in watchdogs or explicitly define any STONITH devices, and also
independently of quorum policies - because AFAIK it seems like the right
choice, there's no technical reason not to do so.
My inclination is to think that this is a good approach to take for
problems that in our best-guess judgment "shouldn't happen".
I'm bringing this to both lists, so that we can hear comments both from
developers and users.
Comments please...
--
Alan Robertson <[EMAIL PROTECTED]>
"Openness is the foundation and preservative of friendship... Let me
claim from you at all times your undisguised opinions." - William
Wilberforce
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