On Fri, 15 Feb 2013, Brad Campbell wrote:

Please don't get me wrong. There is no nice way of protecting fools from 
themselves short of revoking their license to breed, it's just from my 
severely opinionated viewpoint that this looks like a sane idea. I'm quite 
prepared to be slapped, and in fact probably need it.

Well, yes, it's a sane idea.

Right now it seems a significant part of new threads started on this list 
is about people doing --create --assume-clean with a different version of 
mdadm (so offset/chunk-size/whatever is wrong) or they have the wrong 
order. In order to help them, I believe the default behaviour of 
--zero-superblock without any additional flags, should be to give hdparm 
style message so that the user understands what is really going to happen, 
and when the superblocks are zeroed, a mdadm --examine and --detail (if 
the array is running) with a UUID/date should be saved somewhere.

The aim would be to drive two things:

People should think thrice about using --create --assume-clean. If they do 
(or do --zero-superblock), detailed information should be saved for the 
array and components before the operation was performed.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se