On Mon, Apr 20, 2015 at 09:26:54AM +0200, Petter Adsen wrote:
> Is it possible to have two VGs on the same PV?
I don't believe so. The VG is the mapping layer in the LVM stack. It
maps the LVs to the PVs. If you were to share a PV between VGs, then
you'd need some way to tell the VGs which parts of the PV they can use
(letting them battle it out and potentially over-commit the PV is not
really a good idea). The easiest idea is to split the underlying device
into multiple PVs (e.g. use partitions).
>
> If so, how can I make a VG with lots of free space smaller? I'm
> suspecting that the answer to my first question is "no", since this
> doesn't seem possible from the man pages.
A quick bit of searching suggests the incantation would be:
* Boot from a rescue/live disc
* Activate your VG
* (You say you've got unallocated space in your VG, so resizing
filesystems/LVs won't be covered)
* "lvm pvs" should, at this point, indicate some PFree, which is how
much you can shrink the PV
* Run "lvm pvresize /dev/whatever --setphysicalvolumesize 50G"
(Where /dev/whatever is the PV device and 50G is the new size to
resize to)
* Finally, resize the PV's partition appropriately.
At this point, you will have a smaller PV and less unallocated space in
your VG. You can now create another partition, PV that and add it to a
second VG.
>
> Petter
>
> --
> "I'm ionized"
> "Are you sure?"
> "I'm positive."
Attachment:
signature.asc
Description: Digital signature