On Tue Jun 02, 2009 at 02:00:15PM +0200, Alexander Rietsch wrote:
>>
>> AFAIK, the only solution at this stage is to recreate the array.
>>
>> You need to use the "--assume-clean" flag (or replace one of the drives
>> with "missing"), along with _exactly_ the same parameters & drive order
>> as when you originally created the array (you should be able to get most
>> of this from mdadm -D). This will rewrite the RAID metadata, but leave
>> the filesystem untouched.
>
> A glimpse of hope. Thank you! Didn't know about this --assume-clean flag.
> So just to double-check:
>
> The array to create would be:
> disc 0: sdi1 <- is now disc 7 and SPARE due to failed replacement operation
> disc 1: sdl1
> disc 2: sdh1
> disc 3: sdj1
> disc 4: sdk1
> disc 5: sdg1
> disc 6: sda1 <- is now faulty removed
>
> So I just create an incomplete array without sda1 in the same order which
> would be:
>
> mdadm --create /dev/md0 --assume-clean --level=5 --chunk=64
> --raid-devices=7 /dev/sdi1 /dev/sdl1 /dev/sdh1 /dev/sdj1 /dev/sdk1
> /dev/sdg1
>
Almost - you'll also need to specify "missing" for disc 6 (and the
--assume-clean isn't actually needed in this case, as the array can't do
any reconstruction with a missing drive), so:
mdadm --create /dev/md0 --level=5 --chunk=64 --raid-devices=7
/dev/sdi1 /dev/sdl1 /dev/sdh1 /dev/sdj1 /dev/sdk1 /dev/sdg1 missing
> I'm not sure about the drive oder in the mdadm command: is it correct to
> assume <drive 0> <drive 1> <drive 2> in order or is it mirrored like <drive
> 2> <drive 1> <drive 0> ?
> I also hope the command doesn't trigger any recovery actions or filesystem
> changes..
This should be safe, yes - the numbers are also given in the output from
"mdadm -D /dev/md0" or "mdadm -E /dev/sdl1". The array creation doesn't
trigger any changes at all to the filesystem (though mounting it might,
even in read-only mode) so is perfectly safe to do. You can also try
"fsck -n" on the filesystem before mounting to verify that the array
order is correct - this may fail on filesystems with unflushed journal
data though.
Cheers,
Robin
--
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( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
/ / ) | Little Jim says .... |
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