On Thu, 23 Sep 2010 16:30:20 -0700 Adam Newham <adam@xxxxxxxxxxxxxx> wrote: > > I've got a sick RAID-5 array and looking for advice on the best way to > fix it. I've Google'd the hell out of it/read the FAQ and think I know > what I need to do but I what to make sure as I'd rather not have to > restore the data from backups (as they're incomplete and would be very > time consuming) > > The machine is configured as follows: > > * 4 x 1 TB drives (SATA) - software RAID-5, with LVM consuming all > 3TB and then ext3 on top giving 2.7 TB > * 1 x OS drive (IDE) (I actually have 1x drive with RHEL5 and > another with Ubuntu which with the newer kernel is a lot more > friendly with my motherboard) > > > Basically I had the machine die due to a bad motherboard and DIMM. > During a boot a disc check was performed and at 1.6% Linux performed a > "kernel panic". I re-installed the OS and I'm now trying to recovery the > RAID. it looks like I have 3x problems. > > * When the original OS was installed, the OS drive was located on > /dev/hda[x]. Under the new OS (Ubuntu 10.04), its now populated at > /dev/sda[x]. The RAID was originally located on /dev/sd[abcd]/ > With the OS drive in /dev/sda[x], the OS is populating the RAID at > /dev/sd[bcde]. I modified the /etc/mdadm/mdadm.conf file to > reflect this. I could probably get round this by going back to the > RHEL5 OS, but it would be nice to know how to do this. > > At the moment I fixed it by modifying the /etc/mdadm/mdadm.conf file as > follows: > > DEVICE /dev/sd[bcde]1 > ARRAY /dev/md0 level=raid5 num-devices=4 > UUID=08558923:881d9efd:464c249d:988d2ec6 > > * The next problem (and is my main problem) is that one of the > drives (/dev/sde) has a checksum error in the superblock. So when > the try to assemble the array, I get the following: > > sudo mdadm --assemble --verbose /dev/md0 > mdadm: looking for devices for /dev/md0 > mdadm: /dev/sde1 is identified as a member of /dev/md0, slot 3. > mdadm: /dev/sdd1 is identified as a member of /dev/md0, slot 2. > mdadm: /dev/sdc1 is identified as a member of /dev/md0, slot 1. > mdadm: /dev/sdb1 is identified as a member of /dev/md0, slot 0. > mdadm: added /dev/sdc1 to /dev/md0 as 1 > mdadm: added /dev/sdd1 to /dev/md0 as 2 > mdadm: failed to add /dev/sde1 to /dev/md0: Invalid argument > mdadm: added /dev/sdb1 to /dev/md0 as 0 > mdadm: /dev/md0 assembled from 3 drives - not enough to start the array > while not clean - consider --force. > > /var/log/messages contains the following: > > md: sde1 does not have a valid v0.90 superblock, not importing! > md: md_import_device returned -22 > > If I dump out the info for the drive (/dev/sde1) I see the following: > > sudo mdadm --examine /dev/sde1 > /dev/sde1: > Magic : a92b4efc > Version : 00.90.03 > UUID : 08558923:881d9efd:464c249d:988d2ec6 > Creation Time : Mon Nov 3 17:42:21 2008 > Raid Level : raid5 > Used Dev Size : 976759936 (931.51 GiB 1000.20 GB) > Array Size : 2930279808 (2794.53 GiB 3000.61 GB) > Raid Devices : 4 > Total Devices : 4 > Preferred Minor : 0 > > Update Time : Sun Aug 15 12:33:06 2010 > State : active > Active Devices : 4 > Working Devices : 4 > Failed Devices : 0 > Spare Devices : 0 > Checksum : e828e258 - expected e828e260 > Events : 143 > > Layout : left-symmetric > Chunk Size : 64K > > Number Major Minor RaidDevice State > this 3 8 49 3 active sync /dev/sdd1 > > 0 0 8 1 0 active sync /dev/sda1 > 1 1 8 17 1 active sync /dev/sdb1 > 2 2 8 33 2 active sync /dev/sdc1 > 3 3 8 49 3 active sync /dev/sdd1 > > How do I fix this? Googling seems to imply recreating the array over the > top and specify the UUID? Should I force the assemble with 3x drives? > There is also a --update which updates the metadata on the disk? Yes. Try those. I would do mdadm --assemble --force --update=summaries /dev/md0 /dev/sd[abcd]1 and see if that works. > > * The last problem is that I believe that one of the drives has > additional metadata. This caused Ubuntu to see an additional > partition /dev/md0lp1 in addition to /dev/md0. What is the best > way of removing it? Did you mean "/dev/md0p1", or was there really an 'l' in there?? That just means that the array (/dev/md0) has a partition table. If you want to remove a partition table, then maybe use fdisk. 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 -- 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
