[CentOS] CentOS Digest, Vol 73, Issue 12

Sat Feb 12 21:21:25 UTC 2011
Chuck Munro <chuckm at seafoam.net>

On 02/12/2011 09:00 AM, Gerhard Schneider wrote:
> Sorry, I don't use CentOS 6 now so I cannot check, but:
> Could it be that RHEL6 changed the default superblock mdadm is creating?
> CentOS 5 is creating a 0.9 superblock. Some "other OS" are creating 1.2
> per default. But you can change that on the command line.
> If that's the case it's not a bug but a feature..
> GS
> -- Gerhard Schneider Institute of Lightweight Design and e-Mail:
> gs at ilsb.tuwien.ac.at Structural Biomechanics (E317) Tel.: +43 664 60 588
> 3171 Vienna University of Technology / Austria Fax: +43 1 58801 31799
> A-1040 Wien, Gusshausstrasse 27-29 http://www.ilsb.tuwien.ac.at/~gs/

Bingo!  That hadn't occurred to me.  And 1.2 is specified in the 
mdadm.conf file, which went right over my head.  :-(

Thanks Gerhard; mystery solved.  Now all I need to do is wait for 
CentOS-6 to see if it correctly assembles all members of the arrays at 
boot time.  I suspect the evaluation copy of RHEL-6 is not really up to 
date, so there may be issues with mdadm.  I did take a look around the 
RedHat bugzilla site and saw a couple of things that might be related to 
the problem.