Nataraj wrote: > fred smith wrote: > >> Thanks for the additional information. >> >> I'll try backing up everything this weekend then will take a stab at it. >> >> someone said earlier that the differing raid superblocks were probably >> the cause of the misassignment in the first place. but I have no clue >> how the superblocks could have become messed up, can any of you comment >> on that? willl I need to hack at that issue, too, before I can succeed? >> >> thanks again! >> >> >> >>> Nataraj >>> >>> > I would first try adding the drives back in with: > > mdadm /dev/mdN -a /dev/sdXn > > Again, this is after having stopped the bogus md arrays. > > If that doesn't work, I would try assemble with a --force option, which > might be a little more dangerous than the hot add, but probably not > much. I can say that when I have a drive fall out of an array I am > always able to add it back with the first command (-a). As I mentioned, > I do have bitmaps on all my arrays, but you can't change that until you > rebuild the raidset. > Note, that if you need to use assemble --force, you must stop the array first and know exactly which drives you want to assemble the array with. > I believe these comands will take care of everything. You shouldn't have > to do any diddling of the superblocks at a low level, and if the problem > is that bad, you might be best to backup and recreate the whole array or > engage the services of someone who knows how to muck with the data > structures on the disk. I've never had to use anything other than mdadm > to manage my raid arrays and I've never lost data with linux software > raid in the 10 or more years that I've been using it. I've found it to > be quite robust. Backing up is just a precaution that is a good idea for > anyone to take if they care about their data. > > If these problems reoccur on a regular basis, you could have a bad > drive, a power supply problem or a cabling problem. Assuming your drives > are attached to SATA, SCSI or SAS controller, you can use smartctl to > check the drives and see if they are getting errors or other faults. > smartctl will not work with USB or firefire attached drives. > > Nataraj > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >