What does read/write latency measure in ESXi?

Read/write latency specifically measures the average delay experienced during disk operations, which is typically expressed in milliseconds. This is a critical performance metric for virtualized environments running on ESXi, as it directly impacts the responsiveness of applications and services that rely on disk I/O.

When latency is high, it indicates that there is a delay in reading from or writing to disk, which can lead to performance bottlenecks. Understanding latency helps system administrators identify potential issues related to storage performance, allowing them to take necessary actions, such as optimizing storage configurations or upgrading hardware if needed.

This metric is particularly important in environments with high disk activity because it can affect not only individual virtual machines but also the overall health and performance of the ESXi host and the data center’s infrastructure.