[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]
I'm trying to run an mdadm raid1 as my root using autodetection during boot (with no initrd). This used to work just fine. Now, however, it seems like the raid device minor numbers are not stable between boots, and sometimes the partition isn't detected at all. I managed to get the system running by supplying an md=126,/dev/sda2,/dev/sdb2 to the kernel, which helped it assemble the array. Some useful info: mdadm --detail /dev/md126 /dev/md126: Version : 0.90 Creation Time : Tue Apr 24 21:22:25 2007 Raid Level : raid1 Array Size : 1052160 (1027.67 MiB 1077.41 MB) Used Dev Size : 1052160 (1027.67 MiB 1077.41 MB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 126 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Wed Jan 12 09:32:22 2011 State : active Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : dae2458d:e144dbde:34d5107b:2f8c859e Events : 0.182 Number Major Minor RaidDevice State 0 8 2 0 active sync /dev/sda2 1 8 18 1 active sync /dev/sdb2 mdadm --examine /dev/md126 mdadm: No md superblock detected on /dev/md126 I suspect that this may be the crux of the matter - something odd is going on with the raid superblocks. I suspect that mdadm can detect and assemble the raid correctly, but the kernel cannot. This makes a direct boot with autodectection impossible. My long-term plan is to move to an initrd and boot with root=UUID=#### which should eliminate any instability issues. In the short-term, I'm thinking about just adding the md= line to my grub.conf. However, what I'd like to know is what happens if one of my drive fails and /dev/sda or /dev/sdb is no longer the same drive that it used to be. What I'd like it to do is mount the root in degraded mode with the one good partition. What I DON'T want it to do is try to treat the second partition on some other random drive as part of that array and do who knows what to it. The behavior of some of this seems sparsely documented. Anybody have any experience with this? Worst case I can always just keep nursing it along until I migrate to an initrd, which should make it all automagical.... ___________________________________________________________________________ Philadelphia Linux Users Group -- http://www.phillylinux.org Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug