On Monday February 25, carlos@fisica.ufpr.br wrote: > Hi, > > I'm trying to re-assemble a raid5 array where one disk failed. The > kernel doesn't auto-start it because the remaining disks have > inconsistent superblocks: .... > The question is how do I use mdctl to assemble the array. I tried > > mdctl -v -A /dev/md2 -f > but got > mdctl: No identity information available for /dev/md2 - cannot assemble. > > What does identity info mean? And how can I force mdctl to assemble > the array? As a last resort, is it possible to edit the superblock and > change the event number? I'll risk it even if fsck complains a lot. > This is an emergency... Identity information simply means how can mdctl identify what devices are part of the array. It needs to know something. It can use UUID, usually out of /dev/mdctl.conf, or device names or super_minor .. You seem to have bits all over the place, so a simple wild card like "/dev/sd?2" wont cut it. Try putting DEVICE /dev/sd* or maybe DEVICE /dev/scsi/host?/bus?/target?/lun0/part? into /etc/mdctl.conf along with ARRAY /dev/md2 super_minor=2 and then run mdctl -v -Asf /dev/md2 and see if that works. This should scan all partitions of all scsi devices looking for super blocks which say that they belong to /dev/md2. It should then try to assemble them, re-writing the superblocks if necessary. > > Is it possible to build a raidtab and user mkraid --really-force even > with one faulty drive? It's easy to discover the partitions, but what > about the order of the disks? If you use mdctl -E /dev/whatever on every partition that you believe to be part of the array, it should tell you how each partition fits into the array, including position. NeilBrown > > Thanks in advance - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
