Re: Device mapper problems..

[Suleyman Kutlu <suleyman.kutlu@gmail.com>]

Lars Ellenberg wrote:

> / 2005-09-16 02:23:46 +0300
> \ Suleyman Kutlu:
>
>  
>
> > Two VGs.
> >
> > systemvg on /dev/sda4
> > datavg on /dev/sdb1
> >
> >    
>
> slightly moving the chunks around in your mail,
> so it is more obvious...
>
>  
>
> > What I am trying to do is:
> >
> > - At least get the directory contents of the filesystem
> >  /dev/datavg/snk2lv inorder to know what I have lost.
> >  Is it possible to get this with jfsutils ??  Any experience ?
> >    
>
> hm...
>
>  
>
> > - If there is a way to fix-up the device-mapper tables and get my
> >  filesystems back, it is ofcourse welcome.
> >    
>
> well, comparing this:
>
>  
>
> > ls -la /dev/mapper
> > total 124
> > drwxr-xr-x   2 root root    4096 Sep 16  2005 .
> > drwxr-xr-x  36 root root  118784 Sep 16 01:49 ..
> > crw-------   1 root root  10, 63 Sep 16  2005 control
> >    
>
>  
>
> > brw-------   1 root root 253,  0 Jun  5 03:24 systemvg-optlv
> > brw-------   1 root root 253,  1 Jun  5 03:25 systemvg-varlv
> > brw-------   1 root root 253,  1 May 10 03:08 systemvg-rootlv
> > brw-------   1 root root 253,  2 Jun  5 03:26 systemvg-tmplv
> > brw-------   1 root root 253,  3 Jun  5 03:26 systemvg-usrlv
> > brw-------   1 root root 253,  4 Jun  5 03:27 systemvg-temp
> >    
>
>  
>
> > brw-------   1 root root 253,  6 Jul 16 20:32 datavg-rootlv
> > brw-------   1 root root 253,  7 Jul 16 22:40 datavg-snk2lv
> > brw-------   1 root root 253,  8 Sep 16  2005 datavg-backup
> >    
>
>  
>
> > dmsetup ls output is:
> >
> > systemvg-optlv (253, 0)
> > systemvg-tmplv (253, 1)
> > systemvg-usrlv (253, 2)
> > systemvg-varlv (253, 3)
> > systemvg-temp  (253, 4)
> > systemvg-rootlv(253, 5)
> >    
>
>  
>
> > datavg-rootlv  (253, 6)
> > datavg-snk2lv  (253, 7)
> > datavg-backup  (253, 8)
> >    
>
>
> for a start,
> we see that the device nodes for -optlv and -temp are correct,
> and the datavg seems correct.
>
> but 253,1 apears two times in the listing, and 253,5 is missing...
>
> recreate those nodes with
> # dmsetup mknodes
>
> or by hand with:
> # cd /dev/mapper
> # rm systemvg-{varlv,rootlv,tmplv,usrlv}
> # mknod systemvg-tmplv   b 253 1
> # mknod systemvg-usrlv   b 253 2
> # mknod systemvg-varlv   b 253 3
> # mknod systemvg-rootlv  b 253 5
>
> now, how this could happen is an other question.
>
> note that maybe the mapping of names to minors is still wrong.
> but at least all of the devices should be there again;
> (253,5) was missing completely before.
>
> hope that gets you one step further.
>
>  

You are right,  datavg seems OK from the device-mapper point of view. 
But at filesystem level, the filesystem on datavg-snk2lv seems to be 4.0 
GB but  in fact it is 80 GB. My opinion is at a point in past, 
device-mapper again scramled the major and minor numbers and 
systemvg-usrlv overwrited datavg-snk2lv.

From dmsetup table output, datavg-snk2lv seems OK. How can I recover 
the filesystem on it ? Or more basic question, is it possible to recover ???

Thanks in advance..

*
* Suleyman Kutlu
* mailto: suleyman.kutlu@gmail.com
*

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