2009/12/4 Neil Brown <neilb@xxxxxxx>: > On Fri, 4 Dec 2009 14:46:39 -0500 > Lucian Șandor <lucisandor@xxxxxxxxx> wrote: > >> Hi all, >> There is a problem with my Linux installation, and the drives get >> renamed and reordered all the time. Now, it just happened that the two >> degraded RAID5s won't return to life. The system would not boot, so I >> panicked and deleted: fstab, mdadm.conf, and some of the superblocks. >> Now Linux boots, but RAIDs are, of course, dead. I tried to re-create >> the arrays, but I cannot recall the correct order and my attempts >> failed. I believe that the partitions are OK, because I don't recall >> re-creating without "missing", but surely the superblocks are damaged >> and certanily most of them are zero now. >> Is there a short way to recover the degraded RAIDs without knowing the >> order of drives? I have 6 drives in one (including "missing"), that >> gives 720 permutations. Also, clearing the superblocks is recoverable, >> isn't it? > > Yes, 720 permutations. But you can probably write a script > to generate them all ... how good are your programming skills? > Use "--assume-clean" to create the array so that it doesn't > auto-resync. Then "fsck -n" to see of the data is even close > to correct. > > And why would you think that erasing the superblocks is a recoverable > operation? It isn't. > > NeilBrown > Thanks for your reply. I didn't realize why googling "recovery after zero superblock" was so inefficient. Sounds very very troubling. I will script it then for the one array with non-zeroes superblocks. One issue is that I didn't use -assume-clean in my early attempts of re-creation. I know this overwrites the superblock. Didn't it make my superblocks as useless as if I zeroed them? Thanks, Lucian Sandor -- 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
