Both ASM and raw use the exact same system calls to issue I/O, so there is no performance difference based on function calls/call stack. The ASM advantage is in the automatic striping of data over the LUNs (ASM disks) - the ASM logical layer. This reduces time to implement a well performing db layout as well as maintenance (disk additions & rebalanced) in the future. In other words, it takes much more time and effort to create a good layout with raw than it does with ASM. On Wed, May 27, 2009 at 1:30 AM, ~Jeff~ <jifjif@xxxxxxxxx> wrote: > Hi all > does anyone know of any papers or study comparing ASM vs raw performance? > We have a vendor deadset on raw, and the DbAs would rather not have to deal > with that! > thanks- > Jeff Wong -- Regards, Greg Rahn http://structureddata.org -- //www.freelists.org/webpage/oracle-l