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RE: Active/Passive "high availability"

From: Kerber, Andrew W. <>
Date: Fri, 13 Apr 2007 14:37:38 -0500
Message-ID: <>

IN rac, while technically you have one database, you should have at least two instances of that database (one per server), and assuming you do not share your oracle home, you also have multiple oracle installations, etc. If your disks are properly mirrored onto separate storage devices, you also have redundancy at the datafile level (including the system tablespace). You just have to set it up correctly  

-----Original Message-----
[] On Behalf Of Kevin Closson Sent: Friday, April 13, 2007 2:06 PM
Subject: RE: Active/Passive "high availability"  

"Oracle RAC provides very high availability for applications by removing the single point

of failure with a single server. If a node in the cluster fails, the Oracle Database

continues running on the remaining nodes. Individual nodes can be shutdown for

maintenance while application users continue to work."  

...this claim is correct (barring bugs).

So, it seems to come down to how you define a "single point". If you look at the "database" as a single point, then yes there is a SPOF, but if you look at it more granularly and consider that the database resides on hardware with mirrored disks and multiple controllers, fibre channels, fans, power supplies, etc. - then there isn't really a SPOF at the database level either because it would really require multiple failures to bring down the database.  

...this point is incorrect. You only have one system tablespace. That is
usually the wart that we point out.  

Data Guard...    

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Received on Fri Apr 13 2007 - 14:37:38 CDT

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