M.2 / NVMe HAT (Pi 5 PCIe)
An M.2/NVMe HAT uses the Raspberry Pi 5's PCIe connector to attach an SSD, letting the node boot from and run on solid-state storage instead of a microSD card. Why it matters: A 24/7 node hammers its boot media with log writes; SD cards wear out and corrupt. An NVMe SSD is far more endurant and faster, dramatically improving long-term reliability for an always-on node. Note: Pi 5 only (PCIe). Set the boot order to NVMe and confirm the PCIe generation/HAT compatibility. On a Pi 4, boot from a USB 3.0 SSD instead.