L
Latency
Definition
Latency in storage refers to the time delay between issuing an I/O request and receiving the response. It is typically measured in microseconds for flash storage and milliseconds for HDDs. Key latency metrics include average latency, p99 (99th percentile), and p999 (99.9th percentile). Tail latency (p99/p999) is often more important than averages for real-time applications because it represents the worst-case user experience.
