Network I/O latency is an important measurement, especially in latency-sensitive applications like those found in industries such as finance and trading, healthcare, transportation, and telecom (in particular, applications using Voice over IP). The end-to-end latency requirements of these applications vary from microseconds to milliseconds. And some of these applications, such as those utilizing Voice over IP, are more sensitive to jitter than end-to-end latency. So an important measurement to consider for vSphere performance in this scope is latency and jitter added due to virtualization.
vSphere performance testing in a recently published white paper shows that there is minimal network I/O latency due to virtualization overhead. The paper looks at several aspects of network I/O latency, including:
- Latency overhead due to virtualization per VM per round-trip
- Round-trip latency between two virtual machines on the same vSphere host
- Impact of using DirectPath I/O on virtual machine response time
- Impact of resource (CPU, network bandwidth) contention on virtual machine response time
The paper also includes consolidation guidelines and best practices that can reduce network I/O latency in your vSphere system.
Read more about Network I/O Latency on VMware vSphere 5.