Normally it is set to the number of physical drives, but it can be adjusted higher or lower depending on how much load you want to drive. Here is a couple command lines and summary that I used from a Sun Thumper(http://www.sun.com/servers/x64/x4500/) for testing I/O bandwidth using 1MB reads for a data warehouse workload. -run advanced -type seq -testname thumper_seq -num_disks 45 -matrix point -num_large 45 -num_small 0 -num_streamIO 16 -disk_start 0 -disk_end 150 -cache_size 0 Maximum Large MBPS=2668.88 @ Small=0 and Large=45 -run advanced -type rand -testname thumper_rand -num_disks 180 -matrix point -num_large 720 -num_small 0 -duration 60 -disk_start 0 -disk_end 150 -cache_size 0 Maximum Large MBPS=1758.35 @ Small=0 and Large=720 On Fri, Sep 12, 2008 at 2:27 AM, LS Cheng <exriscer@xxxxxxxxx> wrote: > Hi > > Does anyone know what value should be used for num_disks argument when > running I/O stress tests with ORION? > > For example consider I have a RAID Group within an EMC Clariion CX-700 SAN, > formed by 8 physical disks and striped using RAID 1+0, then from this RAID > Group 4 LUN are created and presented to the server. > > What is the value for num_disks, 8 or 4? -- Regards, Greg Rahn http://structureddata.org -- //www.freelists.org/webpage/oracle-l