Hello list, I seem to be in severe trouble because my software RAID 5 is not accessible anymore, needless to say the data on it is important to me ;) I use the four disks hde, hdf, hdg, hdh. I'm 100% sure my /etc/raidtab has correct and actual settings: raiddev /dev/md0 raid-level 5 nr-raid-disks 4 nr-spare-disks 0 persistent-superblock 1 parity-algorithm left-symmetric chunk-size 128 device /dev/hde1 raid-disk 0 device /dev/hdf1 raid-disk 1 device /dev/hdg1 raid-disk 2 device /dev/hdh1 raid-disk 3 Yesterday there were two power outages. After the first, I saw one of the hdds rebuilding (hdd led was on all the time). After the second outage, the md0 was not recognised correctly anymore after startup. I think, the important lines from /var/log/boot.msg are the following: hdh1's event counter: 0000001c hdg1's event counter: 0000001c hdf1's event counter: 0000001a hde1's event counter: 0000001b superblock update inconsistency kicking non-fresh hdf1 from array! kicking faulty hde1! not enough operational devices for md0 (2/4 failed) Now I read the ideas in http://www.faqs.org/docs/Linux-HOWTO/Software-RAID-HOWTO.html#ss6.1 ("Recovering from a multiple disk failure") and played with a test raid system (md1) a little bit. I found out the following: - If I create a new raid for testing (md1 on hdd1 to hdd4), stop it, damage one disk (I formatted it), then do a "mkraid /dev/md1 --force", all data is lost. - If I mark the faulty disk as "failed-disk" in /etc/raidtab, then do a "mkraid /dev/md1 --force", the raid is present again, albeit in degraded mode. A "raidhotadd /dev/md1 /dev/hdd1" would launch a rebuild. Now my question is: According to the messages displayed above, I figure out that disk hde1 is damaged, disk hdf1 has a wrong superblock. I would do the following : 1. Mark hde1 as failed-disk in /etc/raidtab 2. Do a "mkraid /dev/md0 --force" 3. Do a "raidhotadd /dev/md0 /dev/hde1" What do you think, will my real data be online again? I really would appreciate your help, thanks in advance, Christof - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
