On Monday April 3, nigel@xxxxxxxxxxxxxx wrote: > I wonder if you could help a Raid Newbie with a problem > > I had a power fail, and now I can't access my RAID array. It has been > working fine for months until I lost power... Being a fool, I don't have > a full backup, so I really need to get this data back. > > I run FC4 (64bit). > I have an array of two disks /dev/sda1 and /dev/sdb1 as a raid5 array > /dev/md0 on top of which I run lvm and mount the whole lot as /home. My > intention was always to add another disk to this array, and I purchased > one yesterday. 2 devices in a raid5?? Doesn't seem a lot of point it being raid5 rather than raid1. > > When I boot, I get: > > md0 is not clean > Cannot start dirty degraded array > failed to run raid set md0 This tells use that the array is degraded. A dirty degraded array can have undetectable data corruption. That is why it won't start it for you. However with only two devices, data corruption from this cause isn't actually possible. The kernel parameter md_mod.start_dirty_degraded=1 will bypass this message and start the array anyway. Alternately: mdadm -A --force /dev/md0 /dev/sd[ab]1 > > # mdadm --examine /dev/sda1 > /dev/sda1: > Magic : a92b4efc > Version : 00.90.02 > UUID : c57d50aa:1b3bcabd:ab04d342:6049b3f1 > Creation Time : Thu Dec 15 15:29:36 2005 > Raid Level : raid5 > Raid Devices : 2 > Total Devices : 2 > Preferred Minor : 0 > > Update Time : Tue Mar 21 06:25:52 2006 > State : active > Active Devices : 1 So at 06:25:52, there was only one working devices, while... > > #mdadm --examine /dev/sdb1 > /dev/sdb1: > Magic : a92b4efc > Version : 00.90.02 > UUID : c57d50aa:1b3bcabd:ab04d342:6049b3f1 > Creation Time : Thu Dec 15 15:29:36 2005 > Raid Level : raid5 > Raid Devices : 2 > Total Devices : 2 > Preferred Minor : 0 > > Update Time : Tue Mar 21 06:23:57 2006 > State : active > Active Devices : 2 at 06:23:57 there were two. It looks like you lost a drive a while ago. Did you notice? Anyway, the 'mdadm' command I gave above should get the array working again for you. Then you might want to mdadm /dev/md0 -a /dev/sdb1 is you trust /dev/sdb 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
