IO devices and latency — PlanetScale

Non-volatile storage, like tapes, hard disk drives (HDDs), and solid-state drives (SSDs), plays a crucial role in modern computing by storing data persistently. Tape storage, once common in the 1950s, is still used today for its cost-effectiveness in storing large amounts of data. HDDs improved upon tape storage with faster random access times due to their circular platters and mechanical read/write heads. SSDs, which use electronic signaling without mechanical parts, offer the fastest performance, though they rely on complex algorithms for data management and garbage collection. As cloud services grow, many databases use network-attached storage for flexibility, though this comes with higher latency. PlanetScale tries to overcome these limitations with its Metal database solution that uses direct-attached NVMe SSDs for high-performance and scalable databases.