8 Concurrent vMotions not working over 10GbE

[Sam30]

I'm on ESXi 5.5 with 1x10GbE NIC on each host dedicated for vMotion vmnics but still I can get only 4 concurrent vmotions per host.

While it should be 8 concurrent vMotions.

Any idea what am I missing or what can I check ?

RTT value is less then 1ms, so there's no latency on my vmotion network.

Thanks in advance

[Sam30 · Accepted solution]

All right so I got the resolution on my own , just thought to share it here.

Just in case, it may help someone.

So here's the deal on my vMotion port group I had 10GbE NIC as Active & 1GbE as standby just in case the 10GbE uplink fails I wanted to keep some redundancy & that's where the problem was.

After removing the standby 1GbE NIC & testing I started getting 8 concurrent vMotions.

So the Portgroup where your vMotion Network resides you cannot add anything less than a 10GbE on source and destination, regardless if it is active or on standby.  The reason would be that if it fails and it is on standby it will fail over to a 1Gb and if that happens and you have more than 4 vMotioning machines going at the time it may all fail and possibly cause damage to the VMs.  So it runs a test to make sure there is only 10GbE in the entire round trip, and if it detects less then it will limit it to 4 concurrent VMs to vMotion.