Question on Computing VG Capacity

Joshua Long <[email protected]> Wed, 6 Aug 2025 21:49:53 +0000
Newsgroups dev.linux.lists.linux-lvm
Message-ID <LV3PR21MB4252594D194D3081D1E50411C12DA@LV3PR21MB4252.namprd21.prod.outlook.com>
Hi everyone,

I wanted to reach out with a question regarding how to compute the exact us=
able capacity of a volume group, based on the disks that will be used,=A0wi=
thout actually creating the VG or physical volumes.

Specifically, I am looking for a method or tool that can help me determine =
the capacity accurately beforehand.=20

For example, I have a VG with a single PV with a PE size of 4194304 B.=20

We have one disk with 1920383410176 B, which equals 457855.084 PE.=20

The capacity of the VG with this PV after creation is 1920378863616 B, equa=
ling 457854 PE.

Is it always true that the total PEs in the VG will be the disk capacity di=
vided by PE size, minus one? Or are there other factors or metadata overhea=
ds I should consider? Any guidance or suggestions would be greatly apprecia=
ted.

Thank you for your time and assistance!

Best regards,
Joshua Long