Data and indexes on different volumes

We are currently running 11.2.0.1 on Oracle Solaris v10... RAID-5 config. We're hoping to move data around in the near future for many reasons - and will likely migrate to ASM soon as well.

In the past, it was recommended that we separate data and indexes on different storage - for optimal performance. But, we've been hearing that is a thing of the past, and there are no performance gains by doing this - especially when running on RAID-5.

Our SA has been hearing the opposite - that if we separate indexes from the data, and put the indexes on faster disk (possibly SSD), we could see up to a 2x gain in performance - since the updating of indexes is an "expensive" operation.

Any thoughts would be very much appreciated.

Thanks!

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