I have been replying directly to you, not to the mailing list, since your case seems to be a case of user-screwed-up-his-own-data, and not a problem with mdadm/linux raid, nor a problem that will necessarily help someone else (since it is not likely someone will create a mess in exactly the same manner you have). Also, it is easier to click reply than reply-all and have to worry about the top-posting police getting on my case. To summarize: 1) You lost a disk. Even down a disk, you should have been able to run/start the array (in degraded mode) with only 2 disks, mounted the filesystem, backed up data, etc. 2) You then should have simply partitioned and then --add 'ed the new disk. mdadm would have written a superblock to the new disk, and resynced the data Would have-- Could have-- Should have--- Hindsight is 20/20, a mistake was made, it happens to all of us at some point or another, (I've lost arrays and filesystems with careless use of 'dd' once upon a time; Once, I was giving a raid demo to a friend with loop devices, mistyped something, and blew something else away) Unfortunately, you might have clobbered your drives by recreating the array. I assume your original disks were in the order sdb, sdc, sdd. If so, you certainly clobbered your superblocks and changed the order when you did this: > ~# mdadm -Cv /dev/md0 --assume-clean --level=5 --raid-devices=3 /dev/sdc1 /dev/sdd1 /dev/sdb1 You changed the order, but because of the assume-clean, it shouldn't have started a resync of the data. Your file system probably had a fit though, since your data was put effectively through a 3-piece strip-type paper-shredder. You should be able to reorder things though.. IMPORTANT: At any point did your drives do a resync? Assuming no, and assuming you haven't done any other writing to your disks(besides rewriting the superblocks), you can probably correct the order of your drives by reissuing the --create command with the two original drives, in the proper order, and the missing drive as the placeholder. (This will rewrite the superblocks again, but hopefully in the right order). mdadm -Cv /dev/md0 --level=5 --raid-devices=3 missing /dev/sdc1 /dev/sdd1 Note, you need the 'missing' drive, so the raid calculates the missing data, instead of reading chunks from a blank drive. If you can start that array with 2 devices (it will be degraded with only 2/3 drives) you should be able to mount and recover your data. You may need to run a full fsck again since your last fsck probably made a mess. Assuming you can mount and copy your data, you can then --add your 'new' drive to the array with the --add argument. (Note, you'll have to clear it's superblock or mdadm will object) -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
