Baker,
The A to B switchover on the Sequoias was manual and we did in fact do
it after about 15 minutes. Only because it provided an excellent
opportunity to do so. The Sequoia Field Engineer was on site with the
new parts (it was one of the 2 power supplys for the drawer of Raid
disks) within 30 minutes.
As far as I know Sequoia is no more. I seem to remember they sold their
hardware business unit to General Automation in the mid 1990's.
Baker Hughes wrote:
Jeff,
Thank you for giving your experience with HA AIX and a cluster. We are also
doing the HA but not clustering. The couple minutes time lag you mention and
the possibility of broken transactions make one wonder if it's worth going that
distance.
I didn't know Stratus was still out there so thanks for that. What about
Sequoia? That was also a very coveted system in the 911 offices back in the day.
Awesome story about the Sequoia still tooling right along while the disk is on
fire. So did the system switch itself over to 'B' or did y'all do it, when?
I can't match that one, but even with Reality 7 (sorry to mention this on the
U2 list) we could throw a manual switch (took me about 30 seconds to get from
my office to the switch in the computer room) and when the dispatchers logged
in, there were their sessions with screens looking identical to system A.
That's why I gotta believe we can do better, 20 years later.
Thank you.
-Baker
-----Original Message-----
From: u2-users-boun...@listserver.u2ug.org
[mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Jeff Schasny
Sent: Monday, July 26, 2010 10:24 AM
To: U2 Users List
Subject: Re: [U2] 24 X 7 MV systems
We are running an IBM high availability cluster of AIX machines which do
auto fail-over. There is a couple minutes of time lag involved and there
can be broken transactions since the switchover is OS level and not
applications based so this is probably not a good solution for you since
it sounds like you are looking for a truly fault tolerant solution.
Stratus is still out there and probably a good choice for your needs. I
know they have at least one series of boxes which run Red Hat and
therefore are U2 compatible.
I worked on a fault tolerant Sequoia system running Pick OA many years
ago supporting an alarm monitoring application. Amazing machines. True
Story: The operations manager gets a call from the computer operator who
tells him "Theres smoke coming out of one of the disk drawers on the
Sequoia 'A' system" (we had a second redundant Sequoia 'B' system as
well). A couple quick phone calls later 5 of us are huddled together in
the computer room on various phones with Sequoia after hitting the raid
disk drawer in question with a fire extinguisher, trying to decide if we
should switch over to the backup system, when out of the little glass
cubicle where the operators live comes the operator on duty. He walks up
to the smoking system, pulls off a spinning magnetic tape, and mounts
the next reel of a file restore he's doing for someone. We all look at
each other and laugh because the system is still running along just fine
while on fire.
Baker Hughes wrote:
Hey y'all,
I'm interested in hearing from folks who are currently on, or have worked with
fault tolerant MV systems.
We'd like to host our Business Layer on the MV system and serve It to our
e-commerce portals, instead of re-coding our business rules first in Basic,
then in .Net In order to get there though we must meet the primary business
requirement of zero downtime (not even 2 minutes to manually switch). We're
not talking about different levels of Raid - it's assumed the storage array is
up and available. If the MV system has a hiccup of more than a few seconds it
needs to hot failover to a backup twin sister.
Is anyone doing this or something close to it? When I worked in public safety,
Stratus sold such an automatic hot failover. I'm sure the EnRoute folks are
doing something like this still. Maybe Nick G. or Margaret M. is listening in
today.
Thanks,
-Baker
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Jeff Schasny - Denver, Co, USA
jschasny at gmail dot com
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