Re: array went wonky

[Gimpbully <gimpbully@gmail.com>]

This is very odd.  When trying to force an assemble, it's syaing no superblock on /dev/sdf1, but the --examine output appears to say otherwise…  Does anyone have any idea how to do this without doing a re-creation?


eduardo ~ # mdadm --examine /dev/sd{f,g,e,a}1 | egrep 'Event|/dev/sd'
/dev/sdf1:
         Events : 25979
this     5       8       81        5      spare   /dev/sdf1
   0     0       8       33        0      active sync   /dev/sdc1
   2     2       8       65        2      active sync   /dev/sde1
   4     4       8        1        4      active sync   /dev/sda1
   5     5       8       81        5      spare   /dev/sdf1
/dev/sdg1:
         Events : 25971
this     1       8       17        1      active sync   /dev/sdb1
   0     0       8       33        0      active sync   /dev/sdc1
   1     1       8       17        1      active sync   /dev/sdb1
   2     2       8       65        2      active sync   /dev/sde1
   4     4       8        1        4      active sync   /dev/sda1
   5     5       8       81        5      spare   /dev/sdf1
/dev/sde1:
         Events : 25979
this     2       8       65        2      active sync   /dev/sde1
   0     0       8       33        0      active sync   /dev/sdc1
   2     2       8       65        2      active sync   /dev/sde1
   4     4       8        1        4      active sync   /dev/sda1
   5     5       8       81        5      spare   /dev/sdf1
/dev/sda1:
         Events : 25979
this     4       8        1        4      active sync   /dev/sda1
   0     0       8       33        0      active sync   /dev/sdc1
   2     2       8       65        2      active sync   /dev/sde1
   4     4       8        1        4      active sync   /dev/sda1
   5     5       8       81        5      spare   /dev/sdf1
eduardo ~ #



On May 1, 2013, at 11:59 AM, Gimpbully <gimpbully@gmail.com> wrote:

> Alright, so I've ddrescued 2 disks now:
> sda - clean
> sdb - SMART errors, kicked out of array
> sdc - SMART errors, kicked out of array
> sde - ddrescued copy of sdb
> sdf - original failed disk, replaced.  is now a ddrescued copy of sdc
> 
> So I run 
> 
> eduardo ~ # mdadm --assemble --force /dev/md127 /dev/sd{f,g,e,a}1
> mdadm: cannot open device /dev/sdf1: Device or resource busy
> mdadm: /dev/sdf1 has no superblock - assembly aborted
> eduardo ~ # 
> 
> Any ideas?
> 
> On Apr 30, 2013, at 7:48 AM, Gimpbully <gimpbully@gmail.com> wrote:
> 
>> I have no intentions of recreating at all.  I fully understand the implications (I've had stripe orders go bad on truly massive scales before, I don't ever wanna experience that again), I just don't know mdadm as well as other vendor storage.
>> 
>> I was able to ddrescue a copy of sdb with no errors.  I assembled the array and got a file system metadata dump (this is HUGE) and it's currently rebuilding before I even look at data.  Thank you all for your help, patience was absolutely key here.
>> 
>> 
>> On Apr 30, 2013, at 7:45 AM, Phil Turmel <philip@turmel.org> wrote:
>> 
>>> On 04/30/2013 02:20 AM, Sam Bingner wrote:
>>>> On Apr 29, 2013, at 4:33 PM, "Gimpbully" <gimpbully@gmail.com>
>>>> wrote:
>>>>> On Apr 13, 2013, at 7:20 AM, Sam Bingner <sam@bingner.com> wrote:
>>>>> 
>>>>>> After that you can try to recreate the array with the proper
>>>>>> order (sdc1, sdb1, sde1, missing, sda1) and copy data off or add
>>>>>> the spare in again depending on if you were able to recover all
>>>>>> the data wih GNU ddrescue.
>>>>> 
>>>>> 
>>>>> What do you mean recreate?  what's the specific command?  something
>>>>> like:
>>>>> mdadm --create --assume-clean --level=5 --raid-devices=5 /dev/md127
>>>>> /dev/sdc1 /dev/sdb1 /sdv/sde1 missing  /dev/sda1
>>>> 
>>>> Don't recreate it - I said the wrong thing... You want to do an
>>>> assemble on them with force if possible... Recreate is last ditch and
>>>> make sure you have another copy if you do the previous command in
>>>> case it doesn't work right due to offsets etc...
>>>> 
>>>> try:
>>>> mdadm --stop /dev/md127
>>>> mdadm --assemble --force /dev/md127 /dev/sd{c,b,e,a}1
>>> 
>>> Yes.
>>> 
>>>> If you DO need to recreate it, what you showed looks correct.
>>> 
>>> NO!
>>> 
>>> The OP has *not* shared sufficient information on the array members to
>>> say that.  Since it has "worked for years", the odds of an offset error
>>> is *very* high.  Chunk size defaults are also likely to be different.
>>> 
>>> *Complete* output of "mdadm -E" for the array members is needed before
>>> any "--create" operation is attempted.  Plus the distro info, kernel
>>> version, and mdadm version .
>>> 
>>> Phil
>> 
> 

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