Symptoms:

High number of the following messages appearing in syslog : snmpd: lookup_vswitch: fetch VSI_MODULE_NODE_PortCfgs_properties failed Not found

syslog.log:2018-11-15T10:43:38Z snmpd: lookup_vswitch: fetch VSI_MODULE_NODE_PortCfgs_properties failed Not found
syslog.log:2018-11-15T10:44:53Z snmpd: lookup_vswitch: fetch VSI_MODULE_NODE_PortCfgs_properties failed Not found
syslog.log:2018-11-15T10:44:53Z snmpd: lookup_vswitch: fetch VSI_MODULE_NODE_PortCfgs_properties failed Not found
syslog.log:2018-11-15T10:44:53Z snmpd: lookup_vswitch: fetch VSI_MODULE_NODE_PortCfgs_properties failed Not found


Syslog logging level is set above WARNING level.

Check the current setting using ;

esxcli system snmp get

VMware vSphere ESXi 6.0
VMware vSphere ESXi 6.7
VMware vSphere ESXi 6.5

These messages are informational and do not present a risk to production services.

An explanation of the available logging levels is available here;

https://pubs.vmware.com/vsphere-6-5/topic/com.vmware.wssdk.pg.doc/PG_Appx_Diagnostics.20.4.html

Set the logging level to WARNING

esxcli system snmp set -l warning

Workaround:

If you wish to maintain a higher level of logging but do not wish to see these warnings, consider filtering your syslog messages;

Filtering logs in VMware vSphere ESXi (2118562)
https://kb.vmware.com/kb/2118562