Re: rac vs dataguard
Date: Fri, 17 Jul 2009 20:38:01 -0400
One thing I forgot to mention.
We will be setting up a physical standby from the primary site, to a DR site.
- Original Message ----- From: David Ballester To: ksmadduri_at_gmail.com Cc: eglewis71_at_gmail.com ; oracle-l_at_freelists.org Sent: Thursday, July 16, 2009 2:19 PM Subject: Re: rac vs dataguard
I'm agree with the points about application scalability, performance, etc... but what's about D&R? For performance you can always tune your application / Oracle / OS layer or add more nodes to the RAC but If you loose the primary site or the whole RAC ( big disaster or big human error ) you will must:
- locate new hardware ( new host ) or make room on existing one.
- Install software ( OS, Oracle binaries, patchsets... )
- restore the whole database and recover as far as you can ( lost some of the newest redo logs ? )
- Start to give service.
- If some data was lost, tell your people to redo it again ( if it's possible )
With the Data Guard you have it done in a few minutes, and near zero data lost.
If you can survive without giving service for all the hours ( days? ) doing the previous steps, go on adding only new nodes to the RAC
But if service is important to you, you can spend a little more money on the iron ( is not so expensive this days ) and mount a Data Guard
You can mount a physical standby to protect the whole service and in the same host, mount a logical standby for reporting purpouses, using both of them the same binaries.
Define the resources for the physical standby as low as possible ( it only will be doing recovery ) and allow more resources for the logical one
If a big disaster occurs, you can activate the physical standby ( modifiying init to allow more resources ) and point the logical one to adquire data from the new primary, as part of your contingence procedure.
What's your opinion?
DReceived on Fri Jul 17 2009 - 19:38:01 CDT