On 10/19/2011 01:06 AM, James Dugger wrote:
> I am trying to build an NAS using Ubuntu Server 10.04. I am using the
> following system:
>
> Intel/Pentium 4 2.6GHz
> 1GB Ram
> Silicon Image 4 port SATA/RAID controller (fakeRAID)
> 4 - 1TB HDD
>
> The HDD's are drives I have used in the past to test and build different
> RAID configs using mdadm. I am trying to build a RAID 1 with 4 disks
> using the following:
>
> Code:
>
> mdadm -Cv -l1 -n4 /dev/md0 /dev/sd{b,c,d,e}1
>
> When I try this I get a "Device or resource busy" error. When I catalog
> the /proc/mdstat I get the following:
>
> Quote:
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
> [raid4] [raid10]
> md3 : active raid10 sdd1[3] sdb1[1] sdc1[0] sda1[2]
> 1953519872 blocks 64K chunks 2 near-copies [4/4] [UUUU]
>
> unused devices: <none>
>
> And When I examine the partitions with mdadm:
> Code:
>
> mdadm --examine /dev/sd{a,b,c,d}1
>
> I get:
> Quote:
> /dev/sda1:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 61f714b5:fe18b25f:adc23f65:cc5a51de
> Creation Time : Sun Jul 10 02:59:45 2011
> Raid Level : raid10
> Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
> Array Size : 1953519872 (1863.02 GiB 2000.40 GB)
> Raid Devices : 4
> Total Devices : 4
> Preferred Minor : 3
>
> Update Time : Mon Oct 17 11:33:19 2011
> State : clean
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 0
> Checksum : 5a46c420 - correct
> Events : 98
>
> Layout : near=2, far=1
> Chunk Size : 64K
>
> Number Major Minor RaidDevice State
> this 2 8 17 2 active sync /dev/sdb1
>
> 0 0 8 49 0 active sync /dev/sdd1
> 1 1 8 33 1 active sync /dev/sdc1
> 2 2 8 17 2 active sync /dev/sdb1
> 3 3 8 65 3 active sync /dev/sde1
> /dev/sdb1:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 61f714b5:fe18b25f:adc23f65:cc5a51de
> Creation Time : Sun Jul 10 02:59:45 2011
> Raid Level : raid10
> Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
> Array Size : 1953519872 (1863.02 GiB 2000.40 GB)
> Raid Devices : 4
> Total Devices : 4
> Preferred Minor : 3
>
> Update Time : Mon Oct 17 11:33:19 2011
> State : clean
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 0
> Checksum : 5a46c42e - correct
> Events : 98
>
> Layout : near=2, far=1
> Chunk Size : 64K
>
> Number Major Minor RaidDevice State
> this 1 8 33 1 active sync /dev/sdc1
>
> 0 0 8 49 0 active sync /dev/sdd1
> 1 1 8 33 1 active sync /dev/sdc1
> 2 2 8 17 2 active sync /dev/sdb1
> 3 3 8 65 3 active sync /dev/sde1
> /dev/sdc1:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 61f714b5:fe18b25f:adc23f65:cc5a51de
> Creation Time : Sun Jul 10 02:59:45 2011
> Raid Level : raid10
> Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
> Array Size : 1953519872 (1863.02 GiB 2000.40 GB)
> Raid Devices : 4
> Total Devices : 4
> Preferred Minor : 3
>
> Update Time : Mon Oct 17 11:33:19 2011
> State : clean
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 0
> Checksum : 5a46c43c - correct
> Events : 98
>
> Layout : near=2, far=1
> Chunk Size : 64K
>
> Number Major Minor RaidDevice State
> this 0 8 49 0 active sync /dev/sdd1
>
> 0 0 8 49 0 active sync /dev/sdd1
> 1 1 8 33 1 active sync /dev/sdc1
> 2 2 8 17 2 active sync /dev/sdb1
> 3 3 8 65 3 active sync /dev/sde1
> /dev/sdd1:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 61f714b5:fe18b25f:adc23f65:cc5a51de
> Creation Time : Sun Jul 10 02:59:45 2011
> Raid Level : raid10
> Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
> Array Size : 1953519872 (1863.02 GiB 2000.40 GB)
> Raid Devices : 4
> Total Devices : 4
> Preferred Minor : 3
>
> Update Time : Mon Oct 17 11:33:19 2011
> State : clean
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 0
> Checksum : 5a46c452 - correct
> Events : 98
>
> Layout : near=2, far=1
> Chunk Size : 64K
>
> Number Major Minor RaidDevice State
> this 3 8 65 3 active sync /dev/sde1
>
> 0 0 8 49 0 active sync /dev/sdd1
> 1 1 8 33 1 active sync /dev/sdc1
> 2 2 8 17 2 active sync /dev/sdb1
> 3 3 8 65 3 active sync /dev/sde1
>
> It is indicating that there is a RAID 10 device md3 in existance and
> active. However I have tried to stop the device with -S command and even
> tried to zero out the superblock for /dev/sd{a,b,c,d}1 and I get a
> device busy error again.
>
> I have reformatted the disks and even zeroed them out using dd however
> it still comes back. I went into the FAKEraid settup just before the
> BIOS posts and checked the status of the card. It indicates that "No
> RAID device to delete" when trying to delete any possible configurations
> in the card. fdisk -l gives the following:
>
> Quote:
> isk /dev/sda: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x00011e81
>
> Device Boot Start End Blocks Id System
> /dev/sda1 1 121601 976760001 83 Linux
>
> Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x5482f9cf
>
> Device Boot Start End Blocks Id System
> /dev/sdb1 1 121601 976760001 83 Linux
>
> Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x2d6b9798
>
> Device Boot Start End Blocks Id System
> /dev/sdc1 1 121601 976760001 83 Linux
>
> Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x3d04945c
>
> Device Boot Start End Blocks Id System
> /dev/sdd1 1 121601 976760001 83 Linux
>
> Disk /dev/sde: 500.1 GB, 500107862016 bytes
> 255 heads, 63 sectors/track, 60801 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x000997d2
>
> Device Boot Start End Blocks Id System
> /dev/sde1 * 1 32 248832 83 Linux
> Partition 1 does not end on cylinder boundary.
> /dev/sde2 32 60802 488134657 5 Extended
> /dev/sde5 32 60802 488134656 8e Linux LVM
>
> Disk /dev/md3: 2000.4 GB, 2000404348928 bytes
> 2 heads, 4 sectors/track, 488379968 cylinders
> Units = cylinders of 8 * 512 = 4096 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 65536 bytes / 131072 bytes
> Disk identifier: 0x00000000
>
> Device Boot Start End Blocks Id System
>
> Notice the md3 device at the bottom of the fdisk print out.
>
> Any help with this would be greatly appreciated.
>
> Thanks
>
> --
> James
>
>

Wow.
Where'd md3 come from? It appears to be a raid10 array.

Looks like from the --examine that the device assignments (/dev/sd?) 
have moved around since the array was created (sda belongs to an array 
consisting of d,c,b,e).

Have a look at:
# ls -l /dev/disk/by_id
and it'll show which drives are assigned to which /dev/sd? letter.

Then (w/out rebooting) take another crack at clearing things out, with:
# mdadm --zero-superblock ...

Then re-create/build the array.

P.S. 4 raid-1 (mirrored) drives seems to be excessive redundancy to me.
Any reason for not going with raid-10, or at least a hot spare or two?

-- 
-Eric 'shubes'

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