Re: librbd: error finding header

[Vladimir Bashkirtsev <vladimir@bashkirtsev.com>]

On 10/07/12 03:17, Dan Mick wrote:
> Well, it's not so much those; those are the objects that hold data 
> blocks.  You're more interested in the objects whose names end in 
> '.rbd'.  These are the header objects, one per image, and are 
> interpreted by rbd info, but I'm concerned that one of them may not 
> exist.
Right on the ball: .rbd for image concerned just does not exist. So how 
can we recover from this? And why it has disappeared in first place? (I 
guess latter may be related to some sort of bug)
>
> On 07/09/2012 03:29 AM, Vladimir Bashkirtsev wrote:
>> On 09/07/12 18:33, Dan Mick wrote:
>>> Vladimir: you can do some investigation with the rados command.  What
>>> does
>>> rados -p rbd ls show you?
>> Rather long list of:
>> rb.0.11.000000002786
>> rb.0.d.0000000054a2
>> rb.0.6.000000002eb5
>> rb.0.d.000000008294
>> rb.0.13.000000000377
>> rb.0.e.000000000629
>> rb.0.6.000000002756
>> rb.0.d.000000006156
>> rb.0.d.000000009b82
>> rb.0.5.000000000c9e
>> rb.0.d.0000000080ba
>> rb.0.f.000000000e75
>> rb.0.6.00000000ab4f
>> rb.0.d.0000000048e4
>> rb.0.d.000000005f67
>> rb.0.13.0000000014ad
>> rb.0.d.00000000e074
>> rb.0.f.000000001a4b
>> rb.0.13.0000000004a3
>> ...
>>
>> How to find out to which image these objects belong?
>>
>>>
>>> On 07/08/2012 10:42 PM, Vladimir Bashkirtsev wrote:
>>>> Hello,
>>>>
>>>> I just hit this error:
>>>>
>>>> error opening image sip.logics.net.au: (2) No such file or directory
>>>> 2012-07-09 15:03:59.935835 7ffbe0673780 -1 librbd: error finding
>>>> header: (2) No such file or directory
>>>>
>>>> Googled around and found that Oliver Francke had similar issue back
>>>> in March. Read your responses but still unclear where to start to
>>>> dig. Just upgraded from 0.47.3 to 0.48, done rolling upgrade and all
>>>> RBD images are OK with exception of this one. Notably as upgrade was
>>>> done while VM was up it continued to run unaffected (ie all data
>>>> inside of VM was written and read as nothing happened). It makes me
>>>> think that there no data loss but mere broken header.
>>>>
>>>> Of course I have a backup of VM and can pull it back in no time but I
>>>> am really interested (and I am sure other ceph users) how to recover
>>>> from such failures?
>>>>
>>>> Regards,
>>>> Vladimir
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>>>
>>>
>>
>>
>