Capacity planning calculator
Proxmox VM Storage Planner
Estimate how much usable pool and backup capacity your VMs need after growth, snapshots and a free-space reserve.
Start with usable capacity
Enter capacity after RAID/ZFS redundancy, not the sum printed on the drive labels. The reserve is space you intentionally leave unused for growth, snapshots, filesystem behavior and operational recovery.
Allocated disk is not used data
A VM can have a 500GB virtual disk while using only 60GB on a thin-provisioned pool. This calculator models used data and expected growth. Thick allocation, disabled discard/TRIM, snapshots and storage format can make actual consumption different.
This planner does not prove that a particular mini PC supports Proxmox, passthrough or a storage controller. Installation, IOMMU grouping, drivers and sustained operation require testing on the target hardware.
Keep backups separate
The backup figure is intentionally reported separately. Backups stored on the same pool do not protect against pool loss. Compression varies with encrypted, compressed and media-heavy guests, so replace the default ratio with a measured value from your own jobs.
Validate after deployment
- Compare planned growth with actual guest and pool usage monthly.
- Verify discard/TRIM behavior for thin-provisioned guests.
- Test snapshot deletion and backup restoration, not only backup creation.
- Alert before the pool reaches the reserve threshold.