For a Nutanix Metro Availability configuration, the Witness VM is a crucial component that acts as a tie-breaker during failure scenarios to prevent a split-brain condition. While the round-trip time (RTT) between the two data sites must be less than 5ms, the latency requirement for communication between the data sites and the Witness VM is less stringent. The maximum supported RTT between a Metro Availability Protection Domain (PD) and the Witness VM must be less than 200ms.

A. 5ms is the maximum RTT allowed between the two data sites in a Metro Availability cluster, not to the Witness VM.

B. 100ms is a possible latency but is not the maximum supported limit; the configuration is supported up to 200ms.

D. 500ms exceeds the maximum supported latency, which would cause instability and potential failure of the Witness mechanism.

1. Nutanix. (2023, December 14). Metro Availability Witness Guide v6.8. Section: Witness VM Requirements and Recommendations. "The round-trip latency between a Metro Availability cluster and the Witness VM must be less than 200 ms."

2. Nutanix University. (2023). Nutanix Business Continuity and Disaster Recovery (NCP-BC) 6.5. Module: Metro Availability. "The Witness VM can be located at a third site, with a maximum RTT of 200 ms from the primary and secondary sites."

3. Nutanix. (2023, December 14). Data Protection and Recovery with Prism Element v6.8. Section: Metro Availability Requirements. "Round-trip latency between a metro cluster and the witness VM must be less than 200 ms."