AX4-5i IOPS Maximum

Hello, the AX4-5i (iSCSI version) will scale to close to its maximum number of drives, which is 60. So, with 9 drives in the system, the drives are usually the bottleneck. You can use the 180 IOPS per drive figure as a rule of thumb, though please remember that's conservative (small random IO, assumes no cache optimizations helping the drives work). Real-world can be more or less depending on your workload. But it's a good planning number for small random IO.

You ask: "It's possible calaculate the IOPS total before install the storage system "

So, yes we can estimate what the disks are capable of: 9 * 180 = 1620 IOPS
(for a small random workload)

Next, how to figure out how much the host can achieve...which is possible if you know your IO profile. Since you've read best practices, you know how to characterize the IO. That is actually the hardest step - estimating read to write percentage, cache hit rates, etc.

Use the RAID algorithms from the Best Practices Guide to determine disk IO load after you have subtracted expected cache hit rates.