Standby or unused Uplink is used after rebooting a ESXi 5.0 Update 1 host

Versions Affected

ESXi 5.0; ESXi 5.0 Update 1

Description

Symptom: Diagnostics.py sequential write performance is poor   and esxtop with n switch shows that 1Gbps network is used instead of  10 Gbps.

Solution

It is due to vmware issues explained on these  KBs on ESXi 5.0 update 1: kb2008144  kb2030006 Workaround I: Remove 1Gbps from the vswitch configuration (validated) esxcfg-nics -l - to find one Gig link ids ( eg, vmnic2 and vmnic3) esxcfg-vswitch -l - to find the vswitch portgroups that use these links esxcfg-vswitch -U vmnic2 vSwitch0  Workaround II: To work around this issue, try setting the NIC Failback option to yes on  vswitch as well port group level.

Tags	Networking; VMware; Troubleshooting