Re: Data Guard/RAC ?

Access wrote:

> Hello,
>
> I'm a bit confused regarding the differences between Data Guard and RAC.
> Does RAC make use of Data Guard ? Can I use Data Guard without RAC ? And
> what would be the (dis)advantages of the latter ? If I want to failover to a
> standby database without any interruption, is Data Guard sufficient ?
>
> Thanks,
> Matthias
>
>

Dataguard and RAC are independent, yes you can use one without the other or both together. Has more to do with single points of failure and geographic separation to a large degree... plenty of details available at tahiti.oracle.com.

Leaving out many of those details, RAC = multiple instances running against a single database, all in one physical location. Good for scalability, good for instance failover, but you still only have a single database = single point of failure.

DataGuard = separate databases typically at different locations. You can configure how "tightly" you want to keep the DataGuard standby (two flavors available) up to date with the primary. Failover will typically involve some interruption, but it might be on the order of only a few minutes if you plan it well.

DataGuard is akin to a "live" off-site backup that's ready to go at a moments notice. RAC, as the name implies, is a clustering technology.

-Mark Bole Received on Wed Jan 05 2005 - 12:42:43 CST