LVM VG Capacity Calculator
Calculate total volume group capacity from combined physical volume extents.
About LVM VG Capacity Calculator
A Volume Group pools the Physical Extents from every Physical Volume added to it (vgextend), so its total capacity is simply the sum of all member PVs' usable extents — this is what lets LVM present multiple physical disks as one flexible storage pool. Free PEs (total minus those already allocated to Logical Volumes) determine how much new LV space is available via lvcreate or how much an existing LV can grow via lvextend.
Formula
VG capacity
VG_capacity = Σ(PV_usable_extents) × PE_size
- E_i
- extents contributed by PV i
- P
- PE size
Worked example
With the default values below, LVM VG Capacity Calculator returns Total VG Capacity (GB) of 2,000.000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- PV Sizes (comma-separated GB)
- 500, 500, 1000
- Physical Extent (PE) Size (MB)minimum 1
- 4
- PEs Already Allocated to LVsminimum 0
- 100,000
Results
- Total VG Capacity (GB)
- 2,000.000
- Free Capacity (GB)
- 1,609.375
- Total Physical Extents
- 512,000
- Free Physical Extents
- 412,000
- Allocated Percentage
- 19.53%
- Number of PVs
- 3
Step by step
- 1Values used
- 2VG capacity
- 3Total VG Capacity (GB)= 2,000.000
- 4Free Capacity (GB)= 1,609.375
- 5Total Physical Extents= 512,000
- 6Free Physical Extents= 412,000
- 7Allocated Percentage= 19.53
- 8Number of PVs= 3
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
What happens if I add a PV with a different PE size to a VG?
You can't — all PVs in a single Volume Group must share the same PE size, since VG capacity is tracked in units of extents. If you need a different PE size, it must be set consistently for the whole VG at creation time (vgcreate -s).
Can I remove a PV from a VG without data loss?
Yes, if there's enough free space elsewhere in the VG — first run pvmove to relocate any extents in use on that PV to other PVs in the group, then vgreduce to remove it, and finally pvremove to release it entirely.
How do I add more capacity to an existing VG?
Add a new physical disk or partition, initialize it with pvcreate, then run vgextend <vgname> <new-pv> to fold its extents into the existing volume group's free pool, immediately available for new or growing logical volumes.