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

From: Jeremy Schneider <jeremy.schneider_at_ardentperf.com>
Date: Mon, 23 Dec 2013 09:32:01 -0600
Message-ID: <CA+fnDAZ+h=5jKN-M93a_wn=grOtK-5agD00DQaBOkFF=H1LydQ_at_mail.gmail.com>

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

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On Mon, Dec 23, 2013 at 8:37 AM, Chris King <ckaj111_at_yahoo.ca> 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..

>


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Received on Mon Dec 23 2013 - 16:32:01 CET