Re: mount failed after xfs_growfs beyond 16 TB

Eric Sandeen
2006-11-03T15:55:47Z

Christian Guggenberger wrote:
>> xfs_db mojo.... ;)
>>
>> Note - no guarantee this will work - practise on an expendable
>> sparse loopback filessytem image by making a filesystem of slightly less
>> than 16TB then growing it to corrupt it the same way and then fixing it up
>> successfully.
>>
>> Once it's corrupted, unmount and run xfs_db in expert mode.
>> The superblock:
>>
>> blocksize = 4096
>> dblocks = 18446744070056148512
>> ...
>> agblocks = 84976608
>> agcount = 570
>>
>> An AG is ~43.5GB, so 570 AGs is 24.8TB. It's to big, and
>> we will only shrink by whole AGs. Hence we have to correct
>> agcount and dblocks.
>
> isn't the AG size 'agblocks * blocksize' == ~324 GB here ?
>
> got further input on a secondray superblock form the colleague:
> looks more reasonable, I'd say. Is there a way to manually recover sb0
> from sb1 ?

you can copy it over field-by-field.... not sure if there's an easier way.

-Eric