Moving physical extents within a PV

A new pvmove feature appeared in 11.31 which lets you move physical extents within a PV. This can be very useful to move PEs to make space for a LV which has a contiguous allocation policy such as the swap LV, /stand or /.

To use this, simply specify a start range and end range, and tell pvmove to move a range of extents within the same PV.

Example:

root@bonyeune[~]# pvmove /dev/disk/disk21_p2:00736-01248 /dev/disk/disk21_p2
Transferring logical extents of logical volume "/dev/vg00/lvol3"...
Transferring logical extents of logical volume "/dev/vg00/lvol4"...
Transferring logical extents of logical volume "/dev/vg00/lvol5"...
Transferring logical extents of logical volume "/dev/vg00/lvol6"...
Physical volume "/dev/disk/disk21_p2" has been successfully moved.
Volume Group configuration for /dev/vg00 has been saved in /etc/lvmconf/vg00.conf

In the previous example, I moved a range of 512 PEs from #736 to #1248 further inside the same PV. This freed up PEs between 736 to 1248.

Is it possible to move around a LV with a contiguous policy using this technique? To my surprise, I tried it, and it the answer seems to yes. But there are some limitations. I'll need to set up a VM to be able to experiment further. There are other interesting commands such as "pvmove -n" which lets you move a whole LV without needing to specify PEs like above. I'll make a better post once I've had to time to try it out.

O.