ESXi5 Hosts cannot host more than 24 guests - VM Network doesn't respond

[jadams159]

ESXi 5.1, Cluster of 6 hosts, running on Cisco UCS M3 blades firmware 2.1(1a).  Leveraging Cisco UCS Fabric Extenders for VDS.

Once I hit the 25th VM, the guest network fo rthat VM does not work, it acts as if it is in the wrong vlan or something, Windows can't communicate.  This happens on any host in the cluster.  Each host has multiple port groups, and the problem can happen with any number of VMs in any port group, but once the host has 25 guests, that 25th guest doen't get network.

However, if I connect a host's NIC to a standard switch, and migrate the 25thh VM's network to that switch, it communicates fine.  So I'm fairly certain it's related to the FEX, but each port group profile on the FEX has 64 ports, so I'm not sure what's going on.

Anyone have any ideas?

[markdjones82]

We had a similar item where ports were getting blocked because the max ports setting was at 32.  I am not a networking expert and we use the 1000v, but may want to check if there is some sort of max port setting.  when you go to the ports and look at the vm not workign what is the status?

[jadams159]

The Vm is "connected", but the IP address in the vSphere client shows up as 0.0.0.0.

There are available ports listed in the summary tab of each port group in the vSphere client.

[markdjones82]

Wish I could help you further but not sure what else to look at off the top of my head.  Are you able to ping gateway or anything like that?

[jadams159]

Nope, can't even ping it's own IP address, much less the gateway.

[asrarguna]

Can you check the VDS properties and see Max. no of ports designated for the host?