vSphere Replication RPO Violations and Sync Failures to OCVS due to Network Path Misconfigurations
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vSphere Replication RPO Violations and Sync Failures to OCVS due to Network Path Misconfigurations

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Article ID: 437417

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Updated On:

Products

VMware Live Recovery

Issue/Introduction

 

  • vSphere Replication reports RPO violations exceeding 7,000 minutes.

  • Initial synchronization or ongoing replication for specific virtual machines halts or proceeds at a severely degraded rate (e.g., 44% completion over 28 hours).

  • Enhanced Replication Mappings report "Connection timed out" errors.

  • Replication logs indicate "Broken pipe" or "Connection reset by peer" errors.

  • Baseline network tests confirm stable bandwidth (e.g., 5Gbps link) and active ICMP reachability.

 

Environment

 

VMware vSphere Foundation (VVF) / VMware Cloud Foundation (VCF)

vSphere Replication (Source: On-Premises, Target: Oracle Cloud VMware Solution - OCVS)

Intermediate stateful firewalls active within the transit path.

 

Cause

Replication traffic degradation is attributed to a combination of physical network and configuration anomalies:

  1. Firewall Rule Omissions: Missing configurations on intermediate transit firewalls restrict or drop stateful replication traffic for specific IP streams.

  2. MTU Mismatch: Discrepancies in Maximum Transmission Unit configurations (e.g., MTU 1500 at the source ESXi hosts vs. MTU 9000 at the OCVS target) force packet fragmentation.

  3. Interface Saturation: Lack of dedicated replication interfaces causes vSphere Replication to default to the management VMkernel adapter. High payload volumes combined with fragmentation lead to buffer exhaustion and TCP timeouts on the management network.

Resolution

Execute the following remediation steps to restore replication health and adherence to RPO parameters:

  1. Firewall Transit Validation: Engage the network administration team to audit all intermediate firewalls. Apply explicit permit rules for the affected ESXi hosts and replication appliances.

  2. Port Verification: Ensure continuous, uninspected bidirectional transit for vSphere Replication ports 31031 (Initial Sync) and 32032 (Ongoing Replication) across the entire data path.

  3. MTU Alignment: Standardize MTU configurations end-to-end. If Jumbo Frames (MTU 9000) are utilized at the target, the source ESXi vSwitches, physical switches, routing instances, and firewalls must explicitly support and be configured for MTU 9000.

  4. Traffic Isolation: Configure a dedicated VMkernel adapter (e.g., vmk3) on all participating source ESXi hosts specifically assigned for vSphere Replication and NFC (Network File Copy) traffic. This prevents saturation of the management interface and isolates the replication TCP streams.

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