rmechaber (5/1/2012)
So, while I've got your attention: is there any? miniscule? significant? write-performance hit in writing to a 2-drive mirror compared to writing the same data to a single disk (assuming a hardware RAID controller)? That's what I was really inquiring about.
Sure, it depends on the RAID controller or storage processor. If it was just one write in absolute isolation, it's going to be minimal, but as disk activity starts to pile up, you can run into problems with the bandwidth of the storage gear altogether. If the storage gear doesn't have enough connections to the drives, or if it uses a small shared connection (like 2Gb FC) across a whole lot of drives, then you can run into a bottleneck there.