Re: Oracle DR Solution

From: David Barbour <david.barbour1_at_gmail.com>
Date: Wed, 31 Aug 2011 11:35:15 -0500
Message-ID: <CAFH+ifc70z0ZXKWChT81uW6nrFo44H5_kFN0TSNOyKLqnmfcEg_at_mail.gmail.com>



Something else you might want to consider is why your primary failed in the first place. In any High-Availability/Disater Recovery scenario, the database is or can be a single point of failure. If you have a corrupt database and you're replicating via storage snapshots or using DataGuard with automatic fail-over, you run the risk of ending up with a corrupt DB at both locations requiring a lot of downtime to restore to point-in-time.

If you have an active/passive DataGuard setup with a delay in applying logs for instance, you have a chance to bring the DR site current until just prior to the failure before you open the DB for use.

I had a similar requirement at my previous employer and we delayed log application for 60 minutes. It was a 7+TB enterprise SAP DB processing a LOT of data. We were located in Florida and particularly for hurricane season, maintained a DR site outside Atlanta. We practiced failing over at least twice a year, and actually switched over at other times for maintenance reasons. Applying the outstanding logs took 5 minutes at the most and we were generally able to perform a complete switchover in just under 10 minutes.

On Wed, Aug 31, 2011 at 10:58 AM, Sanjay Mishra <smishra_97_at_yahoo.com>wrote:

> Jason
>
> Yes it was my mistake to say no downtime but actually it is least downtime.
> Ofcourse we can use Fast Start failover to minimize the switcover/failover
> time based on business requirements and avoid some manual intervention.
>
> So What I can see is the Dataguard and Storage based replication as two
> main choices but want to see how Storage based can provide more better
> solution over dataguard on technical side and not on financial terms and
> what is best practices in critical online environment
>
> TIA
> Sanjay
>
> ------------------------------
> *From:* jason arneil <jason.arneil_at_gmail.com>
> *To:* saurabhmanroy_at_gmail.com
> *Cc:* oracle-l_at_freelists.org
> *Sent:* Wednesday, August 31, 2011 8:47 AM
>
> *Subject:* Re: Oracle DR Solution
>
> One drawback with the dataguard route is the "… no loss or downtime"
> requirement.
>
> Sure data guard and be configured to ensure no data loss, but it can't give
> you *no *downtime.
>
> Is that no downtime really a requirement? If you are serious about that,
> you have to go to some form of Active - Active setup across datacentres,
> with stretched RAC as a possibility.
>
> I'd also argue that there are few businesses that really in a catastrophic
> scenario can't afford a handful of minutes to enact a failover.
>
> jason.
>
> --
> http://jarneil.wordpress.com
>
>
>
> On 31 Aug 2011, at 11:35, saurabh manroy wrote:
>
> Extended/Stretch RAC is a low cost but rather incomplete DR solution.
> Low Cost: In-terms of number of resources need to maintain the environment.
> DataGuard maintenance needs additional skills (apart from knowing RAC).
> Also, not to forget licensing costs for DataGuard.
> Incomplete: Distance between nodes of cluster is still a major factor.
> Though 11g comes with preffred mirror read options, internode communication
> would still be an issue over long distance. So, less distance between nodes
> means, both sites would likely stop functioning in situations of: flood,
> earthquake etc.
>
> Since Cost is not an issue for Sanjay, Primary DB as a RAC cluster and
> Standby DB also a RAC cluster would be a better solution in my opinion.
>
> Regards,
> Saurabh Manroy
> http://smanroy.wordpress.com
>
>
> the reader of this email (and attachments) is not the intended recipient,
> you are hereby notified that any dissemination, distribution or copying of
> this communication is strictly prohibited. Please notify the sender of the
> error and delete the e-mail you received. Thank you.****
> ** **
> *From:* oracle-l-bounce_at_freelists.org [mailto:
> oracle-l-bounce_at_freelists.org] *On Behalf Of *Sanjay Mishra
> *Sent:* Tuesday, August 30, 2011 3:28 PM
> *To:* oracle-l_at_freelists.org
> *Subject:* Oracle DR Solution****
> ** **
> Hi****
> ** **
> I am looking to see what is the best option to have DR solution that can be
> Primary with no loss or downtime. Looking for best practices even it is
> expensive solution. Appreciate for any document or link as I am sure lots
> has done work on it. One of the requirement is that database is around 10Tb
> and transaction logs will be be not more than 50G in an hour.****
> ** **
> 1. Can see 11g Active Dataguard which can be used for Reporting as well as
> DR solution****
> 2. Storage Replication****
> ** **
> Rgds****
> Sanjay****
>
> This email and any attachments are confidential and may also be privileged.
> If you are not the addressee, do not disclose, copy, circulate or in any
> other way use or rely on the information contained in this email or any
> attachments. If received in error, notify the sender immediately and delete
> this email and any attachments from your system. Emails cannot be guaranteed
> to be secure or error free as the message and any attachments could be
> intercepted, corrupted, lost, delayed, incomplete or amended. Standard
> Chartered PLC and its subsidiaries do not accept liability for damage caused
> by this email or any attachments and may monitor email traffic.
>
> Standard Chartered PLC is incorporated in England with limited liability
> under company number 966425 and has its registered office at 1 Aldermanbury
> Square, London, EC2V 7SB.
>
> Standard Chartered Bank ("SCB") is incorporated in England with limited
> liability by Royal Charter 1853, under reference ZC18. The Principal Office
> of SCB is situated in England at 1 Aldermanbury Square, London EC2V 7SB. In
> the United Kingdom, SCB is authorised and regulated by the Financial
> Services Authority under FSA register number 114276.
>
> If you are receiving this email from SCB outside the UK, please click
> http://www.standardchartered.com/global/email_disclaimer.html to refer to
> the information on other jurisdictions.
>
>
>
>
> --
> Niall Litchfield
> Oracle DBA
> http://www.orawin.info
>
>
>
>
>
>

--
http://www.freelists.org/webpage/oracle-l
Received on Wed Aug 31 2011 - 11:35:15 CDT

Original text of this message