VMware Aria Operations Continuous Availability (CA) is a feature in VMware Aria Operations (integrated with VMware Cloud Foundation 5.2) that provides high availability by splitting analytics nodes across two fault domains (datacenters) with a Witness Node in a third location to arbitrate in case of a split-brain scenario. The Witness Node has specific network requirements for latency and bandwidth to ensure reliable communication with the primary and replica nodes. These requirements are outlined in the VMware Aria Operations documentation, which aligns with VCF 5.2 integration.
VMware Aria Operations CA Witness Node Network Requirements:
Network Latency:
The Witness Node requires a round-trip latency ofless than 100msbetween itself and both fault domains under normal conditions.
Peak latency spikes are acceptable if they are temporary and do not exceed operational thresholds, but sustained latency above 100ms can disrupt Witness functionality.
Network Bandwidth:
The minimum bandwidth requirement for the Witness Node is10Mbits/sec(10 Mbps) to support heartbeat traffic, state synchronization, and arbitration duties. Lower bandwidth risks communication delays or failures.
Network Stability:
Temporary latency spikes (e.g., during 20-second intervals) are tolerable as long as the baseline latency remains within limits and bandwidth supports consistent communication.
Evaluation of Each Datacenter:
Datacenter A: <30ms latency, peaks up to 60ms during 20sec intervals, 10Mbits/sec bandwidth
Latency: Baseline latency is <30ms, well below the 100ms threshold. Peak latency of 60ms during 20-second intervals is still under 100ms and temporary, posing no issue.
Bandwidth: 10Mbits/sec meets the minimum requirement.
Conclusion: Datacenter A fully satisfies the Witness Node requirements.
Datacenter B: <30ms latency, peaks up to 60ms during 20sec intervals, 5Mbits/sec bandwidth
Latency: Baseline <30ms and peaks up to 60ms are acceptable, similar to Datacenter A.
Bandwidth: 5Mbits/sec falls below the required 10Mbits/sec, risking insufficient capacity for Witness Node traffic.
Conclusion: Datacenter B does not meet the bandwidth requirement.
Datacenter C: <60ms latency, peaks up to 120ms during 20sec intervals, 10Mbits/sec bandwidth
Latency: Baseline <60ms is within the 100ms limit, but peaks of 120ms exceed the threshold. While temporary (20-second intervals), such spikes could disrupt Witness Node arbitration if they occur during critical operations.
Bandwidth: 10Mbits/sec meets the requirement.
Conclusion: Datacenter C fails due to excessive latency peaks.
Datacenter D: <60ms latency, peaks up to 120ms during 20sec intervals, 5Mbits/sec bandwidth
Latency: Baseline <60ms is acceptable, but peaks of 120ms exceed 100ms, similar to Datacenter C, posing a risk.
Bandwidth: 5Mbits/sec is below the required 10Mbits/sec.
Conclusion: Datacenter D fails on both latency peaks and bandwidth.
Conclusion:
OnlyDatacenter Ameets the minimum network requirements for the Witness Node in Aria Operations Continuous Availability. Its baseline latency (<30ms) and peak latency (60ms) are within the 100ms threshold, and its bandwidth (10Mbits/sec) satisfies the minimum requirement. Datacenter B lackssufficient bandwidth, while Datacenters C and D exceed acceptable latency during peaks (and D also lacks bandwidth). In a VCF 5.2 design, the architect would recommend Datacenter A for the Witness Node to ensure reliable CA operation.
References:
VMware Cloud Foundation 5.2 Architecture and Deployment Guide (Section: Aria Operations Integration)
VMware Aria Operations 8.10 Documentation (integrated in VCF 5.2): Continuous Availability Planning
VMware Aria Operations 8.10 Installation and Configuration Guide (Section: Network Requirements for Witness Node)
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