[mythtv-users] OT: follies with RAID

[Yan Seiner]

Martin Bene wrote:
>> Note that sdd is the raw drive, not a partition.
>>
>> selene:/data/home/yan#  /sbin/fdisk -l /dev/sdd
>>
>> Disk /dev/sdd: 400.0 GB, 400087375360 bytes
>> 255 heads, 63 sectors/track, 48641 cylinders
>> Units = cylinders of 16065 * 512 = 8225280 bytes
>> Disk identifier: 0x00000000
>>
>> Disk /dev/sdd doesn't contain a valid partition table
>>
>> As opposed to
>>
>> selene:/data/home/yan#  /sbin/fdisk -l /dev/sdg
>>
>> Disk /dev/sdg: 400.0 GB, 400088457216 bytes
>> 255 heads, 63 sectors/track, 48641 cylinders
>> Units = cylinders of 16065 * 512 = 8225280 bytes
>> Disk identifier: 0x000315f4
>>
>>    Device Boot      Start         End      Blocks   Id  System
>> /dev/sdg1               1       48641   390708801   fd  Linux raid
>> autodetect
>>
>>
>> How do I go about fixing this?
>>     
>
> Should be fairly easy: remove sdd from the raid array, partition it, add /dev/sdd1 to the array.
>
> cat /proc/mdstat
> ==> Check that the array is fully operable, i.e that there are no failed drives/partitions (if output is the same as  in your mail, it's OK)
>
> mdadm --fail /dev/md10 /dev/sdd
> ==> device /dev/sdd is marked as failed in the raid array
>
> mdadm --remove /dev/md10 /dev/sdd
> ==> device /dev/sdd is completely removed from the array
>
> sfdisk -d /dev/sdg | sfdisk /dev/sdd
> ==> repartition sdd just like sdg - if you don't have sfdisk on your system, just partition the drive manually using fdisk
>
> mdadm --add /dev/md10 /dev/sdd1
> ==> Add partitioned device back into array. This will cause a resync of /dev/sdd1.
>
> Bye, Martin
> PS: Warning: the mdadm commands are from memory; should be OK but still..
>   
Your memory is very good.... Worked like a charm.  I'm always skittish 
about messing with raid; I don't do it enough to have a lot of 
confidence in my own knowledge.

--Yan