[mythtv-users] OT-RAID 5 failure. MDADM experts? Seagate 1.5TB failure

[George Mari]

Mark wrote:
> Hello,
> I have been bitten by a firmware issue on the new Seagate 1.5TB drives.  
> Before the firmware update on the drive, they go offline. I have now 
> updated the firmeware on the drives, but two went off-line in a 4 drive 
> RAID 5. 
> 
> Two are degraded now and I am unable to start the array.
> Details.  /dev/sdb,c,d,e built previously with mdadm and was working fine.
> Now, I am unable to assemble ( even with force ) my /dev/md0 as two are 
> failed.
> 
> Here is the mdadm examine on the 4 drives:
> 
>  mdadm -E /dev/sd[b-e]1
> mdadm: No md superblock detected on /dev/sdb1.
> /dev/sdc1:
>           Magic : a92b4efc
>         Version : 0.90.00
>            UUID : e0dc7a82:21d0f971:f1bb1dea:a305e5a8
>   Creation Time : Thu Dec 11 09:08:21 2008
>      Raid Level : raid5
>   Used Dev Size : 1465135872 (1397.26 GiB 1500.30 GB)
>      Array Size : 4395407616 (4191.79 GiB 4500.90 GB)
>    Raid Devices : 4
>   Total Devices : 4
> Preferred Minor : 0
> 
>     Update Time : Sun Dec 14 12:17:42 2008
>           State : active
>  Active Devices : 4
> Working Devices : 4
>  Failed Devices : 0
>   Spare Devices : 0
>        Checksum : 2a871ffd - correct
>          Events : 953875
> 
>          Layout : left-symmetric
>      Chunk Size : 256K
> 
>       Number   Major   Minor   RaidDevice State
> this     1       8       49        1      active sync   /dev/sdd1
> 
>    0     0       8       33        0      active sync   /dev/sdc1
>    1     1       8       49        1      active sync   /dev/sdd1
>    2     2       8       65        2      active sync   /dev/sde1
>    3     3       8       17        3      active sync   /dev/sdb1
> /dev/sdd1:
>           Magic : a92b4efc
>         Version : 0.90.00
>            UUID : e0dc7a82:21d0f971:f1bb1dea:a305e5a8
>   Creation Time : Thu Dec 11 09:08:21 2008
>      Raid Level : raid5
>   Used Dev Size : 1465135872 (1397.26 GiB 1500.30 GB)
>      Array Size : 4395407616 (4191.79 GiB 4500.90 GB)
>    Raid Devices : 4
>   Total Devices : 4
> Preferred Minor : 0
> 
>     Update Time : Sun Dec 14 12:25:06 2008
>           State : clean
>  Active Devices : 2
> Working Devices : 2
>  Failed Devices : 2
>   Spare Devices : 0
>        Checksum : 2a95b019 - correct
>          Events : 953892
> 
>          Layout : left-symmetric
>      Chunk Size : 256K
> 
>       Number   Major   Minor   RaidDevice State
> this     2       8       65        2      active sync   /dev/sde1
> 
>    0     0       8       33        0      active sync   /dev/sdc1
>    1     1       0        0        1      faulty removed
>    2     2       8       65        2      active sync   /dev/sde1
>    3     3       0        0        3      faulty removed
> /dev/sde1:
>           Magic : a92b4efc
>         Version : 0.90.00
>            UUID : e0dc7a82:21d0f971:f1bb1dea:a305e5a8
>   Creation Time : Thu Dec 11 09:08:21 2008
>      Raid Level : raid5
>   Used Dev Size : 1465135872 (1397.26 GiB 1500.30 GB)
>      Array Size : 4395407616 (4191.79 GiB 4500.90 GB)
>    Raid Devices : 4
>   Total Devices : 4
> Preferred Minor : 0
> 
>     Update Time : Sun Dec 14 12:25:06 2008
>           State : clean
>  Active Devices : 2
> Working Devices : 2
>  Failed Devices : 2
>   Spare Devices : 0
>        Checksum : 2a95aff5 - correct
>          Events : 953892
> 
>          Layout : left-symmetric
>      Chunk Size : 256K
> 
>       Number   Major   Minor   RaidDevice State
> this     0       8       33        0      active sync   /dev/sdc1
> 
>    0     0       8       33        0      active sync   /dev/sdc1
>    1     1       0        0        1      faulty removed
>    2     2       8       65        2      active sync   /dev/sde1
>    3     3       0        0        3      faulty removed
> 
> 
> If I try to assemble with the 3 (  mdadm -A /dev/md0 /dev/sd[c-e]1 ) I 
> get the results below:
> 
> mdadm: cannot open device /dev/sde1: Device or resource busy
> mdadm: /dev/sde1 has no superblock - assembly aborted
> 
> 
> Ideas on what to try?
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> 

Read through these, and see if they help -

http://www.mail-archive.com/linux-raid@vger.kernel.org/msg07815.html

http://kev.coolcavemen.com/2007/03/how-to-recover-a-raid-array-after-having-zero-ized-superblocks/

If /dev/sde1 cannot be opened, make sure it hasn't been comandeered 
after a reboot into another array by checking the contents of /proc/mdstat.