[linux-lvm] lvconvert -m 0 /dev/varlin/distfiles /dev/md0 => zero filled logical volume

[Stuart Gathman]

On 03/16/2016 05:36 PM, Raimonds Cicans wrote:
> Hello.
>
> I am trying to move LVM setup from old RAID md0 to new RAID md1
>
> I did "lvconvert -m 1 /dev/path/to/logical_volume /dev/md1" on bunch 
> of logical volumes.
> Everything went without problems.
>
> Then I tried to remove md0 from one of logical volumes by running 
> command:
> lvconvert -m 0 /dev/varlin/distfiles /dev/md0
>
> I tried to mount this logical volume, but failed.
>
> Then I checked first  megabyte of logical volume it was zero filled.
>
> Partial output of "lvs -o+devices":
>   LV              VG     Attr       LSize   Pool Origin Data% Meta% 
> Move Log Cpy%Sync Convert Devices
>   backup          varlin -wi-ao---- 100,00g                          
> /dev/md0(6304)
>   backup          varlin -wi-ao---- 100,00g                          
> /dev/md0(8544)
>   data            varlin -wi-ao----  20,00g                          
> /dev/md0(28384)
>   distfiles       varlin -wi-a-----  20,00g                          
> /dev/md1(2738)
>   ftp             varlin rwi-aor---  10,00g 100,00           
> ftp_rimage_0(0),ftp_rimage_1(0)
>   ftpdown         varlin rwi-aor---  10,00g 100,00           
> ftpdown_rimage_0(0),ftpdown_rimage_1(0)
>
>
> lvm2: 2.02.116
> kernel: 4.4.2
>
>
> Questions:
>
> 1) What I did wrong?
I would have used pvmove.  Using lvconvert, I think you needed to sync 
the mirrors before removing a leg.
> 2) Is it possible to salvage /dev/varlin/distfiles or I must restore 
> it from backups?
Use the metdata backups (/etc/lvm) to restore lvm to before you removed md0.
> 3) What I should do now to get system to safe state?
The system is probably fine - you just removed you data.