I have a fileserver with a 5 disk RAID-5. Things were going along swimmingly with it for about a year, until one day it rebooted (I assume because of a power blip/outage). md0 was never assembled. Instead, it tried to assemble md_d0. I have no idea what md_d0 is. I never tried to create md_d0. I don't even know what md_d0 is supposed to represent. Upon boot, md would add one *random* drive to md_d0. This means different drive letters, different drive contents, no rhyme or reason to the whole thing. It would literally pick one out of the 5 disks in my array and add it to md_d0. I am not joking when I say it's a different disk every time. It is, and only one disk. It would not bother to try to assemble md0 at all. It just tosses one and only one random drive into md_d0: [ 77.968028] md: bind<sdc1> I have verified it's a different disk every time by md5sum of the first kilobyte on each disk. Every time I reboot it is a different drive with a different drive letter. mdstat looks like this: --snip-- Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md_d0 : inactive sdc1[1](S) 976759936 blocks unused devices: <none> --snip-- In the past I fixed this by stopping md_d0, removing the offending drive from it, assembling md0, and adding the offending drive from md_d0 back to the array (after zeroing its superblock with mdadm --zero-superblock). This would result in a RAID resync, but after that completed all was well. My fileserver was up for about a month after performing this procedure without problems. This morning I woke up and my clock was blinking, so I had a bit of a power blip at my place. My fileserver had rebooted, and I find it again in the exact same state: no attempts to assemble md0, and one random drive added to md_d0. Is there a permanent solution to this problem? Where is md_d0 even coming from? How do I permanently get rid of it? -- Tony Arcieri -- 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
