Well, I found my error thanks to your comments about dm. While it's true that the /dev/mapper/sdxx devices are the same as /dev/sdxx , in my case this wasn't entirely true, as the disks i added had a primary partition on them, but i deleted them and made that primary partition a little smaller. However, dm mappings are only loaded on boot normally, so these were not reloaded . Result : the reshape took place on the older "larger" partitions instead of the new, slightly smaller ones. Ofcourse, the superblock was in that area too ofcourse. I restored the partitions to their original larger size and was able to get the superblocks read, and have succesfully recreated a degraded 7 disk array and all data is still intact :) I guess i really should be more carefull using mapper and real devices when changing partition layout. Thanks for the assistance. On Saturday 23 May 2009 23:05:35 you wrote: > On Sun, May 24, 2009 1:03 am, rdc wrote: > > Yesterday i grew my 4*500GB raid5 array to 7*500GB. The reshape operation > > ended succesfully according to the logs : > > > > May 22 22:24:56 [kernel] md: md2: reshape done. > > May 22 22:24:56 [kernel] RAID5 conf printout: > > May 22 22:24:56 [kernel] --- rd:7 wd:7 > > May 22 22:24:56 [kernel] disk 0, o:1, dev:dm-3 > > May 22 22:24:56 [kernel] disk 1, o:1, dev:dm-0 > > May 22 22:24:56 [kernel] disk 2, o:1, dev:dm-2 > > May 22 22:24:56 [kernel] disk 3, o:1, dev:dm-1 > > May 22 22:24:56 [kernel] disk 4, o:1, dev:dm-8 > > May 22 22:24:56 [kernel] disk 5, o:1, dev:dm-6 > > May 22 22:24:56 [kernel] disk 6, o:1, dev:dm-5 > > The devices in your array are dm-xx devices, but.... > > > However, upon restarting this morning the grown array was no longer > > detected, > > and my investigation revealed that the 3 device that were added do not > > contain > > an md superblock at all ! > > > > One of the 3 new devices : > > mdadm --examine -v /dev/sdb1 > > mdadm: No md superblock detected on /dev/sdb1. > > ... you are looking on sdxx devices for the superblock. This > seem to me to be a strange thing to do. > What does > mdadm --example /dev/mapper/whatever > show? > > What exactly are the dm-xx devices? > > NeilBrown -- 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
