CompTIA Linux+ XK0-006 (V8) Practice Question

The pvmove command copies every allocated physical extent on the specified physical volume to free extents on other physical volumes in the same volume group while the logical volumes remain active. After pvmove completes, /dev/sdb no longer contains any used extents and can be removed with vgreduce or pvremove. vgreduce can only detach a physical volume that is already empty; it will fail (or destroy data with --force) if extents are still present. pvremove merely wipes the LVM label and cannot run until the PV has been taken out of the volume group. vgexport exports the entire volume group's metadata and does not migrate extents at all. Therefore, only pvmove /dev/sdb achieves the required live migration.