Sean H. wrote:
To preface, I'm a fairly new Linux user, and have little experience with RAID. I've taken this question several places and have yet to get an answer which solves my problem, so I figured I'd come to the experts. I have a five-disk RAID 5, and one of the disks is failing. Every few days it'll start buzzing, and will continue buzzing until the drive is forced to spin down and back up, by either a restart or suspending to RAM. Now, today, I wanted to determine which disk was failing, so I unmounted my array and unplugged drives - Specifically, three. The third was the culprit, and I plugged the drives back in and rebooted. The gift, or in this case, curse of my motherboard is that it supports hot-swapping of SATA drives. So the drives didn't just disappear inside the OS and reappear after a reboot. They disappeared and re-appeared in the OS with incorrect /dev/sd* locations, and then I rebooted. I was unable to boot until I removed the line detailing the array from my fstab. Now, when I manually 'mdadm --assemble /dev/md0' mdadm finds the two untouched drives, then stops and tells me that they're not enough to start the array. So... How can I reassemble the array without knowing what order the drives are in?
Don't list individual component devices in mdadm.conf. Use array UUIDs instead. I.e., instead of: --- WRONG --- ARRAY /dev/md1 devices=/dev/sda1,/dev/sdb1,/dev/sdc1 --- WRONG --- use this: --- RIGHT --- ARRAY /dev/md1 UUID=11111111:22222222:33333333:44444444 --- RIGHT --- Or use modern ways to assemble the arrays - such as homehost (requires version 1 superblock). In either case mdadm will find the relevant components (assuming DEVICE line in mdadm.conf is correct) and figure out the right order. /mjt -- 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
