In agreement with Dale, while I understand the need to test basic
functionality (i.e. do all the tapes restore, and applications run), ant
the need to fit the test within the purchased test time, and the
convenience of running a test in a virtual machine configured to match
your home system, I would consider part of the DR test to test your
ability to quickly restore and run in a real disaster situation where, I
would think, you will NOT be running second level and the environment
will not necessarily match your home system. Therefore you need to test
how flexibly your configuration responds (or not) to real conditions you
will encounter in a real disaster, and first-level performance is a side
benefit.
just my .02
Dale R. Smith wrote:
I restored VM in an LPAR at DR tests twice a year for over 15 years and
never had a problem with it. Everybody says that performance is not an
issue at a DR test, until people complain about it or you can't finish the
test in the alloted time slot! Believe me, performance can be an issue,
(more on the z/OS side than VM, of course). During most of my DR tests,
the box VM was running on was generally bigger than what I had on the home
system! :-)>
The real key to running VM in an LPAR at DR is to make sure that all
required changes are well documented. Try to keep all the virtual
addresses the same at DR as the home system and remember that the real
addresses may vary from DR site to DR site and even from test to test, (in
other words don't hard code anything unless you are prepared to change it).
if you can keep the virtual addresses the same and it's the same type of
device, then you shouldn't need to change any configuration files. Make
sure you have some way to bring your VM system up without starting any
virtual machines, (AUTOLOG1 should do nothing or very little), until you
have had a chance to make directory changes and configuration file
changes, (if necessary). One way to do this is to query the CPUID and
only do a "normal" start up if you are running on your home system.
Our "normal" IPL only starts a few machines, the operator has to enter a
STARTVM command to bring everything up. This is useful for weekend
testing also!
- Re: Disaster Recovery Scenarios Stanley Rarick
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