Hardware & Power Calculators
Estimate UPS runtime, ZFS usable capacity, and VM density before you rack the gear.
Assumes healthy battery and steady load. Add margin for inverter startup and leave 20% headroom.
Raw: 32 TB. Two-disk fault tolerance; safer for large disks and home labs. Uses ~10% overhead for padding/metadata.
Leaves headroom for hypervisor + storage services. Adjust overhead if you oversubscribe CPU or run heavy workloads.
Quick picks by role. Adjust PSU sizing and UPS targets based on idle/load draw.
Dell R720 / R730 (2U rack)
2x Xeon E5 v2/v3 (12-16 cores total) · 64-128 GB ECC · 8-12x 3.5" bays + optional boot SSD
Idle 130W · Load 280W
Great for Proxmox + ZFS; louder, higher idle; add iDRAC on mgmt VLAN.
HP T630 / T640 Thin Client
AMD GX or Ryzen Embedded (4 cores) · 8-16 GB · 1x M.2 SATA + internal USB
Idle 9W · Load 20W
Excellent tunnel/proxy/metrics node; silent; limited RAM for heavy VMs.
Lenovo M720q Tiny (65W PSU)
Intel 8th/9th Gen i5/i7 (6 cores) · 16-32 GB · 1x NVMe + 1x 2.5" SATA
Idle 12W · Load 55W
Great K3s/containers; add 2.5GbE USB NIC for dual-homing.
Supermicro E300-9A (embedded)
Atom C3558 (4 cores) · 8-32 GB ECC · M.2 + 2x SATA
Idle 20W · Load 45W
Strong firewall/router appliance; multiple NICs; low power.