Tools

The arithmetic I keep redoing, written down once. Each one runs entirely in your browser — nothing is submitted and nothing is stored.

• ZFS and RAIDZ capacity calculator

  How much of a pool you actually get to use, once parity, the TB-to-TiB conversion and the 80% fill line have taken their share.

• UPS runtime estimator

  How long the batteries hold at a given load, and whether that is long enough for everything to shut down cleanly.

• Subnet and CIDR calculator

  Network, broadcast, usable range, mask and wildcard for any IPv4 prefix — including the /31 and /32 cases most calculators get wrong.

• Proxmox memory overcommit planner

  Add up what the guests are allowed to take, subtract what the host and ARC need, and find out before the swapping starts.