Re: recovering from raid5 corruption

[Shaya Potter <spotter@gmail.com>]

On 04/29/2012 07:45 PM, NeilBrown wrote:
> On Sun, 29 Apr 2012 19:29:10 -0400 Shaya Potter<spotter@gmail.com>  wrote:
>
>> On 04/29/2012 06:52 PM, NeilBrown wrote:
>>>
>>> You've written a new superblock 4K in to each device, where previously here
>>> was something.   So you have probably corrupted something though we cannot
>>> easily tell what.
>>>
>>> Retry your experiment with --metadata=0.90.  Hopefully one of those
>>> combinations will work better.  If it does, make a backup of the data you
>>> want to keep, then I would suggest rebuilding the array from scratch.
>>
>> ok, thanks, that was a huge help.
>>
>> I have it setup correctly now (obvious due to the fact that I can read
>> the lvm configuration without any gibberish when ordered correctly).
>
> I should add that this only proves that you have the first device correct,
> the rest may be wrong.
> You need to activate the LVM, then look at the filesystem and see if it is
> consistent before you can be sure that all devices are in the correct
> position.

true, but that also brings my permutations down to 2 (based on my 
assumption that disks in slot 2 (missing), 3 (uncorrupted), are correct. 
  so hopefully restoring lvm doesn't mess up any other data (though 
probably have to make sure that ext3 doesn't do any journal 
reading/writing in an attempt to mount to see if setup correctly as well).