RAID 0 - Stripe Size For Best All Around Performance?

[stevecs]

Generally yes, if you take your average (80% rule) request size and then you set your stripe stripe size so that stripe size * (stripe_width - parity drives) <= request size.

Now this is _NOT_ linear, this scales better when you have a higher degree of parallelism of your requests. This is common here when you run streaming tests say (your queue length is close to 1 generally). This is not what you see in heavy use environments which is one reason why you have to really watch your workloads (request size, queue depth, request type (random,sequential), et al).

Generally if you take the time to map out all the combinations of stripe size/request size the difference is minimal. It's more of a function of queue depth or request size for your performance.

I've attached an example here for a raid-6 array (24 drives, all combinations of stripe size and request sizes from 64KiB to 16GiB). This was a fast test and the only one I had handy on the USB key here as I had this argument recently at work.