One problem with the current LVM module is there is often no way to use an entire physical volume. So, say I have two physical volumes, P1 and P2, and, I want to use all of PV1, it's size is 460.1 GB
Well, there is no way ti exactly use that amount.
From the command line, one can use:
lvcreate -l 100%PVS -n Data MainVG /dev/md0
as an example, this will exactly consume 100% of the size of the physical volume.
What I am doing here is a more advanced config. One PV is raid, the other is not. So, I want to consume 100% of the raid PV for data, and, none of the non raid PV. The non raid PV will be used for snapshots as there is no reason to raid them.