[linux-lvm] Device mapper problems..

[Suleyman Kutlu]

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 at gmail.com
*