<soapbox on>
As, most everyone who subscribes here knows, I am a big fan of hot backup.
That's two simultaneously active NetViews. The biggest reason is
operations. I never met an operator yet who didn't understand "move to the
other box" as a plan, but I have seen them screw up just about everything
else that required a series of steps. I was a systems guy at a customer
site for 8 years, before joining IBM, and I used to have to write the
backup procedures and train folks to do them. In the end, success
depended on who was the shift supervisor at the time of failure.
It's relatively easy to have two NetView and keep them in synch, and even
easier in 7.1 with the new hot backup facility (nvpause and nvresume),
which allows you to pause the daemons, rather than stop them, during
whatever slack period you choose to make a copy of your databases. Or you
can just have two independent NetViews. I have seen installations where
in fact they have three.
The thing about HACMP that most folks don't realize is that NetView is not
designed nor optimized for it. The ideal HACMP secnario is the case where
the running app can be killed and restarted on another box immediately
with no recovery procedures required. But that is not the case with
NetView. The daemons keep large amounts of data in memory, and if you
suddenly crash the box, it is likely that the databases are out of synch.
You will almost certainly have to do ovtopofix -A ( for one map or -a for
multiples) BEFORE you start using NetView again, or else you risk the
dreaded database corruption. Ideally you would start everything but
netmon and do that before continuing. And since NetView "knows" where it
is, you need to move not only the disks to the backup machine but also the
network interfaces. It can be done, and there folks doing it, but it is
not trivial and there are plenty of possibilities for error.
A second NeView gives you the comfort of being able to continue operations
virtually uninterrupted while you bring the failed box back up. Hardware's
the cheapest part of the computing equation in the long run. Buy a
another box.
</soapbox off>
James Shanks
Level 3 Support for Tivoli NetView for UNIX and NT
Tivoli Software / IBM Software Group
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