I've encountered a scenario before where the customer allocated 5 LUNs for the DATA and 4 LUNs for the RECO and then I asked him the RAID configuration behind those LUNs.. and he told me that the DATA are RAID5, then the RECO are RAID10.. well, I don't want to "argue" which one is better or faster but I let our decisions based on facts,numbers,figures Since we are just on the build stage of the RAC environment.. I insisted that we run some benchmarks against the RAID5 and RAID10 disks and whatever the results of the benchmarks will decide where we will place the DATA diskgroup.. luckily he has an open mind.. apparently the RAID10 was 2x faster.. See the results here http://karlarao.tiddlyspot.com/#%5B%5BRAID5%20and%20RAID10%20comparison%5D%5D -- Karl Arao karlarao.wordpress.com karlarao.tiddlyspot.com -- //www.freelists.org/webpage/oracle-l