Advice regarding Cisco/Juniper/HP

Bill Stewart nonobvious at
Wed Jun 23 04:22:55 UTC 2010

On Thu, Jun 17, 2010 at 6:52 AM, James Smith
<james at> wrote:
> we're in the process of  building a DR site.

Assume for purposes of discussion that all the vendors have equivalent
quality equipment with approximately equivalent features.
I can think of four occasions you'd need a DR center
1 - Practicing your disaster-recovery drills
2 - Testing out new configurations or equipment that you'll roll out
to the main system
3 - When you're having a really bad day and need to switch over quickly
4 - When you're having a really really bad day due to common-mode
failures of your main-system's vendor's equipment.

Case 1 is fine.
Case 2 may let you do proofs of concept, but if the DR isn't a close
enough model of your real equipment, it's often not good enough
Case 3 is the canonical time that you want your DR center to look as
much like the real thing as possible, especially if you're trying to
handle partial failures of the main system and not just
smoking-hole-in-the-ground disasters.
Case 4 is the canonical time you wish you'd ignored my advice for
Cases 2 and 3, because your HP box has different bugs than your Cisco

Depending on quite what you do and what your failure models are, you
may be able to build parts of your DR center using other vendors'
equipment, without too much risk of mismatched configurations, but in
general you're going to need to buy a lot of parts for your DR center
that are identical to the primary systems they're backing up.

             Thanks;     Bill

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