RE: RAC Vs Standby Database between Primary and Secondary Data Centers

From: Goulet, Dick <>
Date: Mon, 21 Jan 2008 12:28:33 -0500
Message-ID: <>


        I have not found any place where I can see that Oracle supports Stretch clusters and given that you have to use ASM on a RAC install I've serious doubts about its functionality. The idea I will agree is not far fetched, but the time lag that can occur is undoubtly can cause serious damage to the cluster. I've run RAC systems before on 10baseT and it was absolutely unacceptable. The time delay for the interlink dragged the system down way too hard. But times change so let me know how your project goes.

Dick Goulet / Capgemini
North America P&C / East Business Unit
Senior Oracle DBA / Hosting
Office: 508.573.1978 / Mobile: 508.742.5795 / Fax: 508.229.2019 / Email: 45 Bartlett St. / Marlborough, MA 01752

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-----Original Message-----
From: Nigel Thomas [] Sent: Monday, January 21, 2008 12:08 PM
To: Goulet, Dick
Cc:; Subject: Re: RAC Vs Standby Database between Primary and Secondary Data Centers


What about "stretch clusters"? You can (allegedly) separate your RAC nodes by several kilometres (up to 30 miles/50 km seems to be regarded as acceptable). Of course that has an impact on interconnect speed so you'd also probably want to partition your workload very carefully - but the theory is plausible (it had better be - my current project is expecting to use a stretch cluster).

So if one data center goes down (maybe it was just short of runway 271 at Heathrow the other day), you still have one/some of your nodes in the surviving centre...

Regards Nigel

  • Original Message ---- From: "Goulet, Dick" <> Sent: Monday, January 21, 2008 3:24:26 PM


    RAC is not a High Availability solution in and of itself. RAC [snip] ... will protect you against a
single server failure in your local data center. Standby can protect you against a single server failure as well, but adds protection for a 9/11 incident at the same time..

Dick Goulet / Capgemini
-----Original Message-----
[] On Behalf Of Bob Robert Sent: Tuesday, January 08, 2008 4:16 PM


I need your opinion regarding setting up High Availability solution between Primary and Secondary Data Centers. Is it better to go with Oracle RAC or Oracle Standby database.

Thanks In Advance,

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Received on Mon Jan 21 2008 - 11:28:33 CST

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