On Monday May 21, brugolsky@telemetry-investments.com wrote:

quoted

One could start a RAID 4/5/6 array over a degraded RAID1 for each
component, (i.e., a degraded RAID1).

 
That was supposed to say "a degraded RAID5+1".

On Tue, May 22, 2007 at 10:40:15AM +1000, Neil Brown wrote:

This doesn't really have anything to do with the metadata used - it is
primarily an implementation issue (though you would need to be careful
picking up the pieces after a crash).

 
Right.  Doing it all automatically would be great, but involves some
kernel work.

What I was suggesting is that one administratively stop an array
built conventionally, and manually start a degraded RAID1 for each
component.  It seems that is possible using "--build".  Then one can
manually assemble the RAID5+1 from those RAID1s, and proceed with the
disk-by-disk replacement while the array is online.  Looks as if that
ought to be possible.  I'll have to give it a try, as soon as I have an
afternoon to tinker [say, ... mid-summer :-/].

Many thanks, Neil.

	-Bill