Hi, my Raid controller is an Adaptec 31205 SAS/RAID controller. The battery was an option, but I didn't know it at purchase time. So I have no battery, but the whole system is on an UPS. I have done quite a few tests using bonnie++, focusing on 'random seek' results, and found out that: 1) linux md raid 10 performs better than Adaptec hardware raid in this field (random seek) by 15%, quite consistently 2) hardware raid is better on sequential output 3) md outperforms it again when coming to sequential read, especially with far layout option. So in fact I think I will use md raid, but still don't know with which layout (3x4 or 1x12). What would you suggest as a benchmarking method ? Simply issue a few big queries that I expect to be usual and see how long it last, or is there a more convinient and or "scientific" method ? Thanks, Franck ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org