I have a filesystem directly on an LV without a partition table. I want to create a partition table and add my filesystem to it with testdisk, which means I need more space before the filesystem. I have an extra PV, but it isn't big enough to contain the filesystem. How can I add the extra space to the beginning of the PV, to make room for a partition table?
After clarification it is possible to do it. Generally speaking there is "begin" and "end" of VG. So first you should shrink the VG by removing free PV. Then you should remove the partition of this PV.
And create partition for your new installation. If you want to have the free space on the begin of the harddisk you should boot from live CD/DVD and move the partitions one by one to the end of the disk (to make the free space on the begin)