Thanks for the response Bill. Neil has responded to me a few times, but I'm more than happy to try and keep it on this list instead as it feels like I'm badgering Neil which really isn't fair... Since my initial email, I got to the point of believing it was down to the superblock, and that --zero-superblock wasn't working, so a good few hours and a dd if=/dev/zero of=/dev/hdc later, I tried adding it again to the same result. As it happens, I did the --zero-superblock, then tried to insert it again and then examined (mdadm -E) again and the block was 'still there' - What really happened was that the act of trying to add it writes in the superblock. So --zero-superblock is working fine for me, but it's still refusing to add the device. The only other thing I've tried is moving the replacement drive to /dev/hdd instead (secondary slave) with an small old HD I had lying around as hdc. [root@space ~]# mdadm -E /dev/hdd1 mdadm: No md superblock detected on /dev/hdd1. [root@space ~]# mdadm /dev/md0 --add /dev/hdd1 mdadm: add new device failed for /dev/hdd1 as 5: Invalid argument [root@space ~]# dmesg | tail ... md: hdd1 has invalid sb, not importing! md: md_import_device returned -22 [root@space ~]# mdadm -E /dev/hdd1 /dev/hdd1: Magic : a92b4efc Version : 00.90.00 UUID : 382c157a:405e0640:c30f9e9e:888a5e63 Creation Time : Wed Jan 9 18:57:53 2008 Raid Level : raid5 Used Dev Size : 488383936 (465.76 GiB 500.11 GB) Array Size : 1953535744 (1863.04 GiB 2000.42 GB) Raid Devices : 5 Total Devices : 4 Preferred Minor : 0 Update Time : Sun Jan 20 13:02:00 2008 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : 198f8fb4 - correct Events : 0.348270 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 5 22 65 -1 spare /dev/hdd1 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 0 0 3 faulty removed 4 4 8 49 4 active sync /dev/sdd1 I have mentioned it to Neil, but didn't mention it here before. I am a C developer by trade, so can easily devle into the mdadm source for extra debug if anyone thinks it could help. I could also delve into md in the kernel if really wanted, but my knowledge of building kernels on linux is some 4 years+ out of date and forgotten, so if that's a yes, then some pointers on how to get the centos kernel config and a choice of kernel from www.kernel.org, or from the centos distro would be invaluable. I'm away for a few days from tomorrow and probably wont be able to do much if anything until I'm back on Thursday, so please be patient if I don't respond before then. Many Thanks, Steve. No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.7/1233 - Release Date: 19/01/2008 18:37 - 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
