Re: Problem recovering a failed RIAD5 array with 4-drives. --RESOLVED

[David Greaves <david@dgreaves.com>]

James wrote:
>>> I don't know the original order of the array before all the problems 
> started. 
>>> Is there a way to determine the original order? 
>> No, unless you have some old kernel logs of the last time it assembled
>> the array properly.
>> The one thing that "--create" does destroy is the information about
>> any previous array that the drives were a part of.
>>
>>> The order that --detail is showing now is the order that appeared after 
>>> issuing the command is it is in the email. (ie: a b c d)
>> Odd.  I cannot reproduce it.
>> I suggest you try different arrangements (of the 3 good drives and the
>> word 'missing') until you find one that 'fsck -n' likes.
>>
>> NeilBrown
>>
>>
> 
> I don't understand how the order of --detail was different than the command 
> line on my system, however....
> 
> YOU ARE A LIFE SAVER!!!
> 
> After going through 21 combinations, beginning to lose all hope and plummeting 
> into eternal despair, combo 22 worked. The array is up and working. All the 
> data (1.3Tb) is there and I'm probably the happiest character on the mail 
> list today. 
> 
> Thanks a bunch for your help.

Funnily enough someone else was having a similar problem on the linux-raid list 
at the same time

Here's a script that may be useful to others in this predicament - a hell of a 
lot quicker than doing it by hand...

The 'is the filesystem safe' test probably wants improving from a read-only mount...

http://linux-raid.osdl.org/index.php/RAID_Recovery
http://linux-raid.osdl.org/index.php/Permute_array.pl

David