Virtual machines, vMotions, and storage may experiences very slow transfer speeds after V2T migration

Products

• VMware NSX
• VMware vSphere ESXi

Issue/Introduction

 

• An NSX-V to NSX-T migration has recently taken place
• Windows File Servers experience slow file transfer speeds
• 500 MB file takes ~10 mins to complete transfer from a Jump Box
• Virtual machines on NSX-T segments may experience general network latency
• VMotions may take longer to complete for VMs on NSX-T segments
• VM is attached to a NSX-T Network Segment with a QoS profile

Environment

VMware NSX-T
VMware vSphere ESXi 6.7

Cause

During the NSX-V to NSX-T migration a Quality of Service profile is created with a maximum bandwidth of 100 Mbps. This QoS profile gets applied by default to all NSX-T segments created during the V2T migration.  This includes all segments VMs are assigned to as well as segments to which all VMKernel ports (such as management vmk, vmotion vmk, and storage vmk) are assigned.

Resolution

This issue is resolved in NSX 3.2.2, 4.1.0, and later releases.

 

Workaround:

For each affected segment, change the QoS profile to either a default profile or create a new one with no bandwidth limitation.

For more details on the QoS segment profile, see: https://techdocs.broadcom.com/us/en/vmware-cis/nsx/nsxt-dc/3-2/administration-guide/segments/segment-profiles/understanding-qos-segment-profile.html

 

Additional Information

Impact/Risks:
While this default QoS profile is assigned, the available bandwidth to components using NSX-T segments is limited to 100 Mbps, reducing the speed of communication and introducing latency.