Thanks for all the help. I am now up and running again and have been stable for over a day. I will now install my new drive and add it to give me an array of three drives. I'll also learn more about Raid, mdadm and smartd so that I am better prepared next time. Thanks again Nigel Neil Brown wrote: > 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
