How fast are the spindles, and what size is your iop? Generally, you can assume 110 per 10k RPM disk, and 180 for 15k RPM disk. This is also assuming a 10ms latency for each iop. And subtract 2 disks per raid group for raid dp (if doing writes, don't if you are doing pure reads). So with around 50 disks (after you subtract the raid dp overhead) you can expect around 5500 iops from that set of disks (assuming 10k rpm disks). For the 112 aggregate, you an expect 98 spindles and 10780 iops. I'm assuming 4k iops, and 10ms latency.

Hope that helps, -Blake

On 10/4/06, Suresh Rajagopalan SRajagopalan@williamoneil.com wrote:

Given a disk IOPS of 100, I'd like to estimate total aggregate IOPS for the following cases:

1. 56 disks, 1 aggregate, RAID-DP size 16
2. 112 disks, 1 aggregate, RAID-DP size 16

I'm only interested in the total raw disk IOPS available in each case, not including considering the filer head. For example, we know that RAID-0 with 56 disks @100 would yield 5600 IOPS.

I don't know how to do this calculation with Data ONTAP's implementation of RAID4 or RAID-DP.

Any assistance would help.

Thanks Suresh