[linux-lvm] How to re-stripe a LV after pvmove?

[Dave Wysochanski]

On Thu, 2007-03-29 at 16:05 +0200, Olle Liljenzin wrote:
> Heinz Mauelshagen wrote:
> > On Thu, Mar 29, 2007 at 01:42:47PM +0200, Olle Liljenzin wrote:
> >   
> >> Hello,
> >>
> >> How can I rearrange a striped volume after pvmove has been run, so that 
> >> I get back the original structure with the stripes equally distributed 
> >> on PVs?
> >>     
> >
> > I need to presume, that IO to the striped LV was going on during pvmove.
> > Hence restoring the old mapping won't help and will lead to data corruption.
> >
> > pvmove back using the destination options of the command.
> >   
> 
> Maybe an example is helpful. After the commands below I have two stripes 
> on sdb2 and one on sdb3. How do I move one of the stripes from sdb2 to sdb4?
> 
> pvcreate /dev/sdb{1,2,3}
> vgcreate vg /dev/sdb{1,2,3}
> lvcreate -i 3 -L100M -n lv /dev/vg
> vgreduce /dev/vg /dev/sdb1
> pvremove /dev/sdb1
> pvcreate /dev/sdb4
> vgextend /dev/vg /dev/sdb4
> lvdisplay -m /dev/vg/lv
> 
> --- Logical volume ---
>   LV Name                /dev/vg/lv
>   VG Name                vg
>   LV UUID                NVBrvT-5fZe-0qKA-LCYA-Z9au-X84A-fXYkx3
>   LV Write Access        read/write
>   LV Status              available
>   # open                 0
>   LV Size                108.00 MB
>   Current LE             27
>   Segments               1
>   Allocation             inherit
>   Read ahead sectors     0
>   Block device           253:2
>   --- Segments ---
>   Logical extent 0 to 26:
>     Type                striped
>     Stripes             3
>     Stripe size         64 KB
>     Stripe 0:
>       Physical volume   /dev/sdb2
>       Physical extents  9 to 17
>     Stripe 1:
>       Physical volume   /dev/sdb2
>       Physical extents  0 to 8
>     Stripe 2:
>       Physical volume   /dev/sdb3
>       Physical extents  0 to 8

looks like you need something like this:

pvmove /dev/sdb2:9-17 /dev/sdb4:0-8