The problem has been solved. It's caused by startup script installed by the broadcom/qlogic driver. As long as you're not using FCoE, you can fix it by logging into your ESXi host and running the following commands then rebooting:  esxcli software vib remove -n scsi-bnx2fc cd /etc/rc.local.d/ rm 99bnx2fc.sh esxcli fcoe nic disable -n=vmnic0 esxcli fcoe nic disable -n=vmnic1  Depending on your setup, adjust vmnic# as needed. I have 2x10g and 2x1gig on my card but only had to do this on the 2x10g ports (vmnic0 and 1) If you try and disable the driver - instead of removing it - and then deleting the .sh file, the .sh file gets restored on next boot so you really have to remove the vib. Watch out for any patches which may reinstall the driver. This change can be found in the release notes for the bnx2fc driver. As of version 1.710.70.v[50,55].2 , this "feature" will be present. Dell helped me find the solution this time but there's at least one other guy who ran into this problem and posted the solution: www.davisphotoworks.com/.../broadcom-bcm57810-fcoe-and-esxi
Building a new host for ESXi 6. Using Dell customized ISO and then updated with latest patch. Have the 2x10GB and 2x1GB broadcom (now qlogic) 57800 card. Firmware is latest 7.12.whatever and driver in vmware seems to be the latest too. In my vmkernel.log, I see the following messages every 2 minutes  2015-06-24T17:08:47.788Z cpu0:33368)<6>host11: fip: host11: FIP VLAN ID unavail. Retry VLAN discovery.2015-06-24T17:08:47.788Z cpu0:33368)<6>host11: fip: fcoe_ctlr_vlan_request() is done2015-06-24T17:08:49.790Z cpu31:33363)<6>host11: fip: host11: FIP VLAN ID unavail. Retry VLAN discovery.2015-06-24T17:08:49.790Z cpu31:33363)<6>host11: fip: fcoe_ctlr_vlan_request() is done I found this article:  http ://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2120523 but don't know how that applies. One of the 10gig links is used and shows as offline in vCenter. The other is showing as unknown (it's not connected). I'm not using FCoE and another R620 with the sam card but older firmware and ESXi doesn't show any FCoE adapters. Is this is a bug? Is there any way around the problem of this FCoE garbage filling up the log? Anyone see this before? 
ESXi 6 and broadcom/qlogic 57800 errors in vmkernel.log