Re: Oracle RAC with Active Data Guard : Maximum Availability Architecture

From: Andrew Kerber <>
Date: Mon, 23 Dec 2013 10:21:42 -0600
Message-ID: <>

Hmm, 99.5 percent availability isnt that hard these days. A standby should be more than sufficient. At 99.5 percent, that gives you roughly 45 minutes of downtime per week if my math is correct. A switchover or failover to a standby can be done in much less time than that.

On Mon, Dec 23, 2013 at 9:32 AM, Jeremy Schneider <> wrote:

> Just one thought... keep in mind that "MAA" is also a marketing term. In
> practice it ends up being sortof synonymous with "maximum complexity
> architecture" and "maximum licensing architecture"... so I think you're
> wise to raise the question of complexity. I've been in plenty of
> situations where RAC and DG were good architectural decision (and the
> systems I'm work on now are RAC+DG aka MAA) - but there are many factors to
> availability and I would recommend asking lots of questions and keeping a
> healthy skepticism!
> We've had downtime situations this year which would not have happened if
> we hadn't moved to RAC - including both software bugs in cluster-specific
> modules and operator errors directly due to new complexity. On the other
> hand, we've also had situations where downtime was reduced because critical
> services stayed up during node failures. And that enabled us to schedule
> maintenance of less-critical broken services for a maintenance window,
> which was impossible before moving to RAC.
> -Jeremy
> --
> On Mon, Dec 23, 2013 at 8:37 AM, Chris King <> wrote:
>> We're architecting a new system, and will need 99.5% availability.
>> Looking over Oracle's MAA options, I see RAC with Data Guard. .. but it's
>> not clear to me how this would actually work to avoid ALL downtime. Won't I
>> still need downtime to apply patches, even if I use rolling patches? And
>> isn't it more complex applying patches when there's a standby involved?
>> Is 99.5% really achievable with this combination?
>> Thanks in advance..

Andrew W. Kerber

'If at first you dont succeed, dont take up skydiving.'

Received on Mon Dec 23 2013 - 17:21:42 CET

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