SUMMARY: SC Firmware version for clock (not SC) failover on F4800/F6800 SC's. (fwd)

From: Vincent Cojot <coyote_at_step.polymtl.ca>
Date: Sun Oct 27 2002 - 11:44:38 EST
Thanks for to:
Scott Howard (for an electrical overview of how clock failover works,
showing that it is not software-related).
Ed Kerekes (for mentionning that he saw clock failover during SunFire
course). Some interesting quotes:

Scott:
Clock failover exists in all Sun Fire's.  It's a feature of the hardware,
not the firmware.  This is of course a good thing, 'cos without your
clock, your domains are dead.  The failover is actually handled by the
system boards.  The two SC's put out a phase-locked clock signal, and
the system boards choose which clock signal to use.  If one clock
disappears, they will fail over to the other.

SC failover is a different matter, and is what was introduced in 5.13.x
This allows for the failover of the non-clock components of the SC.

[ snip ]

OK.. "Pulling" the active system controller is a different matter. If
you physically pull out the SC whilst it is active there is a chance it
will cause the domains to crash. The correct procedure is to poweroff/
disable the controller (from within the SC shell) and then remove it.
When you poweroff the controller the clock will fail over to the other SC.
---- end quote -----

,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,
Vincent S. Cojot, Computer Engineering. STEP project. _.,-*~'`^`'~*-,._.,-*~
Ecole Polytechnique de Montreal, Comite Micro-Informatique. _.,-*~'`^`'~*-,.
Linux Xview/OpenLook resources page _.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'
http://step.polymtl.ca/~coyote  _.,-*~'`^`'~*-,._ coyote_at_step.polymtl.ca

They cannot scare me with their empty spaces
Between stars - on stars where no human race is
I have it in me so much nearer home
To scare myself with my own desert places.       - Robert Frost



---------- Forwarded message ----------
Date: Fri, 4 Oct 2002 04:18:11 -0400 (EDT)
From: Vincent S. Cojot <coyote@step.polymtl.ca>
To: sunmanagers@sunmanagers.org
Subject: SC Firmware version for clock (not SC) failover on F4800/F6800
    SC's.


Hello everyone,

I am being told here in Europe that system clock (yes, the actual clock)
failover between the two SC's (system controllers) in a Sunfire F4800 or
F6800 platform isn't functionnal if you have firmware revision 5.12.6
(i.e: lower than than 5.13.x) or below. It is a known issue that System
Controlleur failover will not work in 5.12.6 or below, we already that but
I'm talking about Clock failover: I.E: if you loose SC0, SC1 is supposed
to be providing the system clock (heartbeat) to all System Boards in all
domains. Also, I was told that if you loose SC0, your domains will
"crash". Can anyone confirm that? Has anyone tried pulling (or lost) an
SC0 with firmware 5.12.x from an F4800 or F6800 platform and seen what
happens? Can you share your experiences (good or bad)? I will summarize.
Thank you.

,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,
Vincent S. Cojot, Computer Engineering. STEP project. _.,-*~'`^`'~*-,._.,-*~
Ecole Polytechnique de Montreal, Comite Micro-Informatique. _.,-*~'`^`'~*-,.
Linux Xview/OpenLook resources page _.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'
http://step.polymtl.ca/~coyote  _.,-*~'`^`'~*-,._ coyote_at_step.polymtl.ca

They cannot scare me with their empty spaces
Between stars - on stars where no human race is
I have it in me so much nearer home
To scare myself with my own desert places.       - Robert Frost
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Received on Sun Oct 27 11:49:02 2002

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