Re: Upgrade to big SUN box or RAC for data warehouse?

> why would implementing RAC increase I/O? is that because of the 2 phase
> commit? So you have to write to multiple datafiles?

RAC by itself won't necessarily increase I/O. But the argument is similar to adding more CPUs to a single server instance. With more CPUs, processes get done with their computations quicker and therefore can turn to waiting for I/O more often. More processes waiting for I/O can cause bottlenecks in I/O. With RAC, you are increasing the number of processors, just not all on the same server.

This doesn't have anything to do with 2PC (which is for distributed databases).

HTH,
Brian

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