Oracle on RHEL is a great combination. The pot gets even sweeter with Fusion-io's iomemory gets added to the mix. Team Red Hat has done some excellent benchmarking to show that a single commodity server with RHEL and ioDrives can deliver mind-blowing throughput and IOPS. If you have a read-heavy Oracle workload on RHEL and can't use Oracle Smart Flash Cache, just use directCache from Fusion-io and get it done.
I am presenting this at the Red Hat mini-theatre at the Oracle Open World 2012.