Dual Redundancy / raid-6 on OS 6

I know with 4.2.x conversions from RAID-5 to RAID-6 can take quite a while on that, so the same would be the case on OS6 (but a few weeks sounds like a long time, though you are using high capacity disks and as it has to sync the disks sector by sector it will take twice as long as it would have with 2TB disks). Not only is there heavy stress on all disks, but a lot has to be moved around to change from distributing single parity to distribute double parity.

You shouldn't need to do another factory default.

I agree an article is needed to describe both ways of setting up RAID-6 (I do miss setting it up via RAIDar too). On multiple systems I have deleted the default volume shortly after it was created and whilst the array had just started syncing. Then I created a new RAID-6 volume. As a new md device is created when you do it the way I did the array syncs much faster (much like how it would when you could choose RAID-6 from the start in RAIDar when running 4.2.x). In my case on the 516 it took just hours to sync.