We are setting up a new piece of hardware to virtualize several of our servers on. Choices are RAID 5, RAID 6, and RAID 0+1.

We are wanting to benchmark all three before we go live with the machine, but I'm not sure how to test the speed.

• Since we will be using it to host VMs, what will the actual disk traffic look like?
• What can I use to see if RAID 6 is too slow?
• Short of setting up the system with all the VM's on it and running that way, then redoing on all the work, I'm not sure how to test it. It them becomes more of a subjective test than an objective one.
• I'm worried that RAID6 will have too much overhead, that RAID5 will be to fragile with 3TB drives and I've never worked with 0+1 at all.

So in short I'd like to setup the base machine (which will be running Linux) and then test the underlying SW RAID for speed. What kind of tool exists to simulate this kind of load? Barring the lack of a specific tool, how about a generic FS testing tool that will simulate different loads?