[CentOS] more software raid questions
incoming-centos at rjl.com
Thu Oct 21 18:17:43 UTC 2010
> Nataraj wrote:
>> fred smith wrote:
>>> Thanks for the additional information.
>>> I'll try backing up everything this weekend then will take a stab at it.
>>> someone said earlier that the differing raid superblocks were probably
>>> the cause of the misassignment in the first place. but I have no clue
>>> how the superblocks could have become messed up, can any of you comment
>>> on that? willl I need to hack at that issue, too, before I can succeed?
>>> thanks again!
>> I would first try adding the drives back in with:
>> mdadm /dev/mdN -a /dev/sdXn
>> Again, this is after having stopped the bogus md arrays.
>> If that doesn't work, I would try assemble with a --force option, which
>> might be a little more dangerous than the hot add, but probably not
>> much. I can say that when I have a drive fall out of an array I am
>> always able to add it back with the first command (-a). As I mentioned,
>> I do have bitmaps on all my arrays, but you can't change that until you
>> rebuild the raidset.
> Note, that if you need to use assemble --force, you must stop the array
> first and know exactly which drives you want to assemble the array with.
It's possible that my drives go back so easily because of the bitmap.
You can probably also use --force with the -a option (hot add).
If you use --force, I would make sure that you are specifying the write
drives/partitions since --force will probably cause whatever partition
you give it to be used in the array regardless of weather it was in the
same array before. So if you use --force, I would check the UUIDs of
the partitions first and make sure they are the same, since --force
would allow you to insert one of your md1 partitions into your md0 array.
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