Re: RAID 5 array recovery - two drives errors in external enclosure

[Tim Bostrom <tbostrom@gmail.com>]

THANK YOU!

To all of you who helped with advice.  I finally waded through 70MB of
log files from the last 6 months on my server and finally figured out
a way to get the correct order.  I had a few logs of 'fdisk -l" which
contained the Disk Identifier.  I matched that up against where I had
the drives in the enclosure and the ata.#'s.   I came up with a short
list of drive letter ordering and just kept trying them with four
drives at a time moving the _missing_ drive around.  Finally, it came
up.

I'm now up with four drives and RO filesystem.  I'm going to try and
backup as much as possible off-disk.  Then I'm thinking that I need to
add the "missing" drive back in and re-build.

Correct?

Thank you again.

Tim

On Fri, Sep 18, 2009 at 1:17 PM, Guy Watkins <guy@watkins-home.com> wrote:
> When you did the create, it trashed 1 drive.  I don't know which one.  As
> long as you don't use that drive, your data should still be there.  By
> "trashed" I mean that it reconstructed the data on that drive, but the data
> was not correct.  As long as you aways have 1 drive missing when doing the
> create, md will not write to the user area of the disks.  Anyway, I think
> someone else indicated which drive that was, but maybe you don't really
> know.  If that is the case, you must try all 5 drives in 4 of the 5 slots!
> I think that would be 6*5*4*3*2 or 720 permutations.  Do you want a new
> list?  :)
-snip-

>
> On Fri, Sep 18, 2009 at 1:41 PM, Tim Bostrom <tbostrom@gmail.com> wrote:
>>
>> I had log output from my array before it started exhibiting issues and
>> dropping off drives in the external enclosure.  It said 256k in my old
>> mdadm -E output.
>>
>> I accidentally did a re-create of 5 drives for a few seconds with 64k
>> chunk size, but then stopped it after it wouldn't mount.
>>
>> i'm hoping I didn't completely destroy this thing.  I had a lot of
>> data on there.
>>
>>
>> -Tim
>>
>> On Fri, Sep 18, 2009 at 9:23 AM, Guy Watkins <guy@watkins-home.com> wrote:
>> > No problem.  Hopefully you can modify the script I sent and make it
>> > generate
>> > the mdadm commands that you need.  I assumed you could anyway.  If you
>> > need,
>> > I can make the changes for you.
>> >
>> > I forgot to ask.  How do you know the correct chunk size?
>> >
>> >
>> >
>> > On Fri, Sep 18, 2009 at 12:12 PM, Tim Bostrom <tbostrom@gmail.com>
>> > wrote:
>> >>
>> >> Thank you - I was looking for a tool or script to get all the
>> >> permutations.  I'm not too good at doing it by hand.  :)
>> >>
>> >
>>
>>
>>
>> --
>> -tim
>
>



-- 
-tim
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