We have been following the BlockIO vs FileIO for iSCSI volumes for ESX discussion, and see how some users get really different iometer results to us when comparing the 2 modes!

We wish to create an iometer test configuration that would allow us to simulate real-world ESX loads, and therefore be more useful for VM capacity planning. We should be able to assume some broad mix of common applications (eg. some database, email, file and print, middleware etc.).

Right now, we have 2 identical DSS units (10 x 146GB SAS drives in R50 in each) and have configured one to use BlockIO & other to use FileIO. But we cannot get FileIO to perform even close to BlockIO (eg. using 4kB rand writes, 3 workers & 3 iSCSI Luns/volumes). So that means our iometer tests are not so useful - maybe we need to use a lot more workers and iSCSI volumes?

Any ideas appreciated.