NFC performance is slow
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NFC performance is slow

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Article ID: 307001

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

•    Cold migrations or migrating virtual machines between different cluster without shared storage is taking a long time. 
•    NFC speed is the situation and there are no other errors
•    NFC for provisioning operations, cold migration and cloning over WAN links taking more time. 

Environment

VMware vSphere ESXi 6.0
VMware vSphere ESXi 6.5
VMware vSphere ESXi 7.0

Cause

NFC is single threaded - performance will always be limited by this and you will never move faster than the single thread. 
NFC is encrypted - you can speed up by disabling SSL and improving the the speed up to 20%, this comes at the expense of security and might not be an option for most environments. 
NFC is synchronous - we must READ/WRITE/CHECK then proceed. 
NFC can only do one operation at a time READ/WRITE/CHECK.
NFC is latency aware - it will throttle when latency transitions are seen.



 

Resolution

•    The provisioning TCP/IP stack can be enabled and configured on the ESXi host for some additional performance https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.vcenterhost.doc/GUID-AC418F24-8E7D-40B6-9D07-A9DB504C7F1B.html

•    You can disable SSL with the KB https://knowledge.broadcom.com/external/article?legacyId=2056830 

•    Avoid using NFC for any deployment or movement of large files where speed is a priority.



Additional Information

Impact/Risks:
NFC's performance-limiting factors prevent it from being used to rapidly deploy VMs across non-shared storage.