Re: [Qemu-devel] qemu 2.9.0 qcow2 file failed to open after hard server reset

[Vasiliy Tolstov <v.tolstov@selfip.ru>]

2017-12-22 12:23 GMT+03:00 Daniel P. Berrange <berrange@redhat.com>:
> On Thu, Dec 21, 2017 at 05:58:47PM -0500, John Snow wrote:
>>
>>
>> On 12/21/2017 05:13 PM, Vasiliy Tolstov wrote:
>> > Hi! Today my server have forced reboot and one of my vm can't start
>> > with message:
>> > qcow2: Marking image as corrupt: L2 table offset 0x3f786d6c207600
>> > unaligned (L1 index: 0); further corruption events will be suppressed
>> >
>> > i'm use debian jessie with hand builded qemu 2.9.0, i'm try to
>> > qemu-img check but it not helps. How can i recover data inside qcow2
>> > file? (i'm not use compression or encryption inside it).
>> >
>>
>> Not looking good if you're missing the very first L2 table in its entirety.
>>
>> You might be able to go through this thing by hand and learn for
>> yourself where the L2 table is (it will be a 64KiB region, aligned to a
>> 64KiB boundary, that all contain 64bit, 64KiB aligned pointers that will
>> be less than the size of the file. the offset of this missing region is
>> not likely to be referenced elsewhere in your file.)

Too hard, client restored backup because he don't want to wait for me =))

>
> Fun. That rather makes you wish that every single distinct type of table
> in QCow2 files had a unique UUID value stored in it, to make forensics
> like this easier :-)
>

=)

-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru