Hi Neil Firstly, thanks! I recovered all the data this evening. 2009/7/9 Neil Brown <neilb@xxxxxxx>: > On Tuesday July 7, gnomeza@xxxxxxxxx wrote: >> >> I'm attempting to recover a RAID5 (6 disks) with zeroed superblocks. >> >> But I'm unable to get the data offsets of some of the disks in the >> array to match what I had before: >> ... >> Data offset for this disk was originally 136, but on recreation, mdadm >> chooses 272... > > It must have been created with mdadm-2.5.6 or earlier > Ta, I downloaded and compiled mdadm-2.5.6. >> After updating data_offset and the checksum of the first disk I >> assembled the array and cryptsetup found its header. (Yay!) > > You would need to update the data_offset on each device. > Thanks again. This info was crucial. The dump of mdadm --examine /dev/sd* I grabbed before I shut everything down showed two out of six disks with data_offset of 272 sectors and the rest with 136. (I didn't think that was weird at first.) I'm guessing this happened because I dumped the info after trying to add the two failed disks back to the array with the new version of mdadm. Following your hint, I recreated the array with data_offset of 136 on all the disks. A script to permute the order of the disks and run mdadm -C --assume-clean && cryptsetup && mount did the rest. So...yay! Mark -- 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
