Re: dm-cache refusing to come up again after a crash

[Joe Thornber <thornber@redhat.com>]

On Fri, Dec 06, 2013 at 08:35:41PM +0100, Steinar H. Gunderson wrote:
> On Fri, Dec 06, 2013 at 08:16:05PM +0100, Steinar H. Gunderson wrote:
> > Well, first of all, it doesn't compile, since you use typename outside of
> > templates :-) Fixing that is easy, though. But afterwards:
> > 
> > root@ubuntu:~/thin-provisioning-tools# ./cache_check /dev/md1
> > examining superblock
> >   superblock is corrupt
> >     bad checksum in superblock
> 
> Sorry, wrong device:
> 
> root@ubuntu:~/thin-provisioning-tools# ./cache_check /dev/cache/metadata 
> examining superblock
> examining mapping array
> no hint array present
> examining discard bitset
> root@ubuntu:~/thin-provisioning-tools# echo $?
> 0
> 
> Does that mean it ought to have worked better? :-)

Yes, this is good news.  The damage is probably in the space maps
which get completely regenerated during a restore/repair.

I see from a later mail that you're having another issue with the
tools.  I wonder if you could email me off list, and we'll work out
how I can get a copy of your metadata.

- Joe