I have a HDD that has 2 partitions. the 2nd partition is the VG and I want to reduce its size. I have reduced the Largest LV in the VG and now have free space in the VG. But, I am clueless on how to proceed to reduce the partiton size so that I can use it for another need.

When done, I expect to have 3 parttions total on the HDD. But first, I could some help in understanding the steps necessary for me to take, to move the free space out of the partition that has the Volume Group. Then, i can use fdisk on that 3rd partition for my needs.

I already know how to expand a Volume group by adding PVs, but, I do NOT know and cannot find how to reduce it to recover the free space in the VG to be used in a new partiton. (Better explained..."I want to reduce the physical partition size that the VG represents.)

Thanks in advance

Hi there GCMartin,

You'll use the lvm pvresize command.

There's a great tutorial here:

http://fedorasolved.org/Members/zcat...-new-partition

From there, the PV can be reduced, allowing you to use fdisk to resize the physical partition the PV resides on. This will require that you actually delete the partition you wish to resize, then create a new partition of the size necessary. It's vital that you change the system ID of the 'resized' partition to 8e (Linux LVM) before you write the new partition table, or else you will destroy the existing PV.

Obviously, as you're dealing with some tricky disk operations, make sure you backup all of the data on the disk, lest a mistake or mistype causes the disk to be wiped. If you need any further clarification, just let me know.

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Handy tutorial - it was a major limitation of LVM that it was (apparently) designed by people who never gave a thought to reducing (or replacing) pvs. Lots of bits had to be "tacked on" later.
I use it only under sufferance.

@syg00,

To be fair, the same method is used when you reduce the physical file system and underlying partition on non-PV systems; Gparted just makes the process 'invisible.'

Yes, I'm aware of that. I subscribe to the theory that this shouldn't need another block device layer to add complexity. I liked zfs on OpenSolaris, and I like btrfs on Linux. Conceptually a much better option. Not that I'd use btrfs in production yet.

Oh, I completely agree; I can't stand LVM systems. Sadly, I'm not king of the world