HDD Health Monitor vs SMART Sniffer

HDD Health Monitor is a free, open-source Windows utility that reads raw S.M.A.R.T. information from physical drives. It shows per-drive health and estimated performance percentages alongside a complete S.M.A.R.T. attribute table. The program scans drives automatically, monitors multiple drives at once, and gives each one its own tray icon and alerts. Notifications can cover temperature, declining health, predictive failure, reallocated sectors, uncorrectable errors, and NVMe critical warnings. While running, it records health and selected attribute snapshots every five seconds and keeps history on disk between sessions. Supported drive types include ATA/SATA, M.2 SATA, NVMe, USB, and SCSI, although available data depends on the drive and controller. USB drives appear shortly after connection and disappear from the selector when unplugged. The standalone executable needs no installer or dependencies, but administrator privileges are required. It supports Windows Vista through Windows 11 and can save a PNG screenshot. The MIT-licensed software costs nothing.

SMART Sniffer monitors disk health and sends warnings to Home Assistant. A lightweight Go agent runs on each monitored machine, where every drive appears as its own Home Assistant device. Its Attention Needed sensor covers ATA, SATA, NVMe, and SAS drives, returning NO, MAYBE, YES, or UNSUPPORTED. When a drive’s health changes, persistent Home Assistant notifications can appear automatically, with options to escalate, de-escalate, or dismiss them automatically. Agents advertise on the local network through mDNS/Zeroconf, allowing Home Assistant to find them without manual IP entry. Filesystem monitoring is optional; for configured mountpoints, it reports total, used, and available bytes plus usage percentage. An integration service call can provide SMART data and assessments for use with Google AI, ChatGPT, Claude, or Ollama. The agent also exposes HTTP endpoints for health, drive summaries, individual SMART data, and filesystem usage. SMART Sniffer is free and MIT-licensed. It requires smartmontools 7.0 or newer for JSON output; some USB enclosures that block SMART passthrough are reported as unsupported with unknown health.