Hi, I have a continuing problem with all my my RAID arrays. I'm moderately confident that it's not a mdadm problem but I hope I can ask here for any tests or ideas to test it before I try reporting it up to the LKML. Thanks in advance. I have a new high-end home server/desktop machine built using an Asus Rampage II Extreme motherboard, an Intel Core i7-980x and (currently) 12GB DRAM. The machine has five 500GB WD RAID Edition drives: RAID 1: /dev/sda, /dev/sdb & /dev/sdc - 3 partitions on each drive creating three 3-drive RAID1 drives RAID 0: /dev/sdd & /dev/sde - currently 1 partition on each drive creating a RAID0. Every time I boot all 5 drives are recognized by system BIOS. There is a BIOS device table printing on the screen and it __always__ shows all 5 drives. If I enter BIOS and look at the storage page all drives are shown. If I do nothing then the system waits 10 seconds, then boots into grub. Grub boots the kernel, the boot process rolls along, gets to where it starts mdadm, and then 50%-75% of the time one or more of the partitions isn't found and mdadm doesn't start the RAID correctly. Now, after booting and RAID not starting correctly, maybe half the time I can look for the drive (ls /dev/sde1 for instance) find it and add it back to the RAID array. Half the time the drive isn't found until I reboot the machine. If I look in dmesg I don't see the missing drive. It's just like it isn't there even though BIOS said it was before booting Linux. The missing drive is not always found on a warm reboot, but is often found on a cold reboot. The problem has been consistent across all the kernels I've tried over the last 2 months. My question is whether this is in any way related to mdadm? I suspect it isn't but thought I'd try to get some ideas on how to test for the root cause of this problem. If it was purely a mdadm problem then even if the RAID wasn't correctly started then wouldn't I still find the drive partitions? I can send along whatever info is needed. I don't know what to supply at this point. Thanks, Mark c2stable ~ # uname -a Linux c2stable 2.6.34-rc5 #1 SMP PREEMPT Mon Apr 26 12:04:14 PDT 2010 x86_64 Intel(R) Core(TM) i7 CPU X 980 @ 3.33GHz GenuineIntel GNU/Linux c2stable ~ # c2stable ~ # cat /proc/mdstat Personalities : [raid0] [raid1] md6 : active raid1 sda6[0] sdc6[2] sdb6[1] 247416933 blocks super 1.1 [3/3] [UUU] md11 : active raid0 sdd1[0] sde1[1] 104871936 blocks super 1.1 512k chunks md3 : active raid1 sdc3[2] sda3[0] sdb3[1] 52436096 blocks [3/3] [UUU] md5 : active raid1 sdc5[2] sda5[0] sdb5[1] 52436032 blocks [3/3] [UUU] unused devices: <none> c2stable ~ # c2stable ~ # ls /dev/sd* /dev/sda /dev/sda4 /dev/sdb1 /dev/sdb5 /dev/sdc2 /dev/sdc6 /dev/sde1 /dev/sda1 /dev/sda5 /dev/sdb2 /dev/sdb6 /dev/sdc3 /dev/sdd /dev/sda2 /dev/sda6 /dev/sdb3 /dev/sdc /dev/sdc4 /dev/sdd1 /dev/sda3 /dev/sdb /dev/sdb4 /dev/sdc1 /dev/sdc5 /dev/sde c2stable ~ # -- 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