On Fri, 9 Jul 2010 13:15:00 +0200
Marek [off-list ref] wrote:

Hi Neil,

thanks for your answer. Do I understand it correctly that porting the  
md driver wouldn't be an option either?

No, not really an option.
Darwin is sufficiently different from Linux that it would really mean writing
a RAID5 driver for Darwin using md as a guide.  You could probably borrow
some code (if the license allowed it which I doubt) but a very large amount
would need to be written from scratch.

NeilBrown

Marek

On 9.7.2010, at 12:22, Neil Brown [off-list ref] wrote:

quoted

On Fri, 9 Jul 2010 12:07:56 +0200
Marek [off-list ref] wrote:

quoted

Hi,

it seems that my email has hit top 5 ranking on google when searching
for "mdadm macosx", but it seems that due to some heavy discussion on
this mailing list it probably went unnoticed.
I would like to ask if someone would be able to elaborate whether
there is a possibility that mdadm would run on Darwin and if so,
whether a port would require a substantial rewrite.

mdadm would not run on Darwin.  It only works with the 'md' driver  
which is
only in Linux.

If you want both Linux and Darwin to be able to access the same  
software RAID
array, you would need to find a format that both understand.
Probably the easiest way would be do discover how MAC OSX formats  
RAID array
and write support for that in mdadm.  Far from trivial, but probably  
possible.

A quick google suggest that RAID5 is not supported in OSX, so that  
would not
be an option.

NeilBrown