Re: mdadm: which device set as source to mirror?

Thanks for your quick response.

It won't matter if I want to use 2 blank partitions to build RAID1;

But now I wish to use mdadm to backup my /home partition, which
already has tons of files on it;

If mdadm happens to choose the other blank partition as source
to do mirroring, all my data on /home will be lost;

Hardware RAID always allows me to choose which partition/drive
to be used as source.

Regards,




On Mon, 2005-09-12 at 08:21 +1000, Neil Brown wrote:

On Sunday September 11, xucs007@yahoo.com wrote:

quoted

Dear Neil Brown,

I'm trying to learn how to use your great mdadm,
one thing I'm not quite sure, and couldn't find
any clue in your man page, is,

During create or assemble mode, for RAID1, which
device mdadm uses as source to make the mirroring?
Is there any differences to determine it
for situations of same-size devices and different-size
devices (>1% differences) ?

I think it copies from the smallest numbered working drive (i.e. drive
0 if that is working, else drive 1, etc).  However it really
shouldn't matter to you.  If you are doing something that depends on
having the right answer to this, you are probably doing it the wrong
way.  

If you would like to discuss it further, I suggest explaining what you
want to do, and why you think you need to know this, to
linux-raid@vger.kernel.org. 

NeilBrown

-- 
  Changsen Xu