mdadm --assemble --force /dev/md0 /dev/sd[a-f]2
After processing for awhile two of the six drives were marked as failed and were dropped out of the array. Using badblocks revealed that both drives had failed sectors in the same areas. ... Ugh! Have I lost all information? It seemed kindof silly that all information would be lost when it was very specific sectors that were dead. Here are the steps I took to save 99.9% of the information on the array. I am not claiming that anyone else will have success using these methods and am not responsible for anyone's mistakes but my own.
1. Back up whatever you can. Using mdadm --assemble --force gave me about 2 hours before the drives were dropped from the array. Doing this a couple of times allowed me to get the latest versions of important files.
2. Get some new drives (but don't get rid of the old data).
3. dd_rescue data. Use dd_rescue to copy over whatever data is still good from the bad drives. In my case I took out two of the good drives from the array and replaced them with the new drives. I then did:
dd_rescue /dev/sdd /dev/sdc
and
dd_rescue /dev/sdf /dev/sde
as sdd and sdf were the drives that were going and sdc and sde were the locations of the new drives. Once the data is copied replace the bad drives with the two that were removed.
4. Re-assemble array. With the new drives in place use 'mdadm --assemble --force' to reconstruct the array. If all goes well you should be done.
Anyway... this is just to let people know that it is possible to save data from dead arrays. Just make sure you plan your steps carefully and think throught the consequences of all of your actions.
Also... thanks to everyone who helped me figure out what steps to take.
-Robey Holderith - 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
