vMotion bandwidth requirements

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

When vMotion takes a longer time and eventually fails with a timeout error, it indicates a bottleneck in the migration process. vMotion is highly sensitive to network latency and bandwidth, as it continuously transfers the VM's memory and state between hosts. A timeout points to a prolonged inability to complete this data transfer.

 

Environment

• VMware vCenter Server 7.x
• VMware vCenter Server 8.x
  
   

Cause

vMotion needs a minimum bandwidth of 250Mbps for successful completion.

Resolution

•  250Mbps is the minimum required bandwidth for a vMotion migration. For example, to perform two concurrent vMotion migrations, you must provision at least 500Mbps of dedicated bandwidth for the vMotion network.
• Greater available bandwidth lets migrations complete more quickly.
• Lack of sufficient bandwidth might impact the performance of virtual machine workloads and potentially lead to migration failure.
• For idle virtual machines with no running workloads and low memory use, you might be able to complete vMotion migrations even when less dedicated bandwidth is available.
• However, vMotion is supported only in environments that meet the bandwidth requirement.
• WAN optimization techniques, such as compression and deduplication, improve throughput but do not count towards the minimum required bandwidth for vMotion.
• Gains in throughput resulting from optimization might vary.
• Even if your environment employs such techniques, you must provision 250Mbps dedicated bandwidth per concurrent vMotion migration.