On 2010-07-26, at 12:33, Brock Palen wrote: > I know the lustre kernel has some patches to MD in there. > We have some x4500 and x4540 that we run lustre 1.6.x on as servers. We > currently use raid5 plus spares. We were wondering about reshaping them into > raid6 by taking in the spare. > > Reading online this appears doable with recent version of mdadm which because > we are on rhel4 for servers we do not have. I didn't know if this ability > was in the lustre kernel, if we build the newer mdadm.
I don't think that our RAID patches take out any functionality, but we have never tested this. I also have no idea about whether the newer mdadm has all of the functionality in the kernel that it needs, unless you are taking the Lustre RHEL5 kernel + RHEL5 mdadm, and just have RHEL4 userspace. That would hopefully be OK, since I doubt if mdadm cares about anything else in userspace, just the kernel. I'd be sufficiently leery of this (even w/o Lustre patches involved) that I'd make a backup of each OST before starting the reshaping. That way, you don't need to have a backup of the whole filesystem at one time, just the one or two OSTs that are currently undergoing reshaping. Cheers, Andreas -- Andreas Dilger Lustre Technical Lead Oracle Corporation Canada Inc. _______________________________________________ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
