software raid auto assembly problem on Xen host

Michael Torrie torriem at
Wed Mar 3 15:00:53 MST 2010

Nicholas Leippe wrote:
> The option you're looking for is --homehost= during array creation.
> It affects the metadata, and depending on the superblock version you
> chose the UUID.
> I don't know if you can change it after-the-fact.
> I do know that only 0.90 superblocks is supported for some operations
> (booting off of raid1 I believe is one of them), despite the 1.0
> version being several years old and improved in a few ways. Go figure.

Unfortunately since RHEL itself made the RAID during install, who knows
if it did the right thing with homehost or not.

If I read the manpages correctly, this is how you would change it after
the fact (as an example):

mdadm -A /dev/md4 --homehost=<vmhostname> --update=homehost --auto=yes
/dev/sdd1 /dev/sdp1

However this had no effect.  The host still happily assembles
everything, even things with this new homehost.  I'm wondering if
there's not a bug in the redhat initrd stuff.

More information about the PLUG mailing list