VMVware vswitch load balancing methods

Load balancing is one of the most important thing in a virtual world. Because we are using few NICs for receiving & sending a data of multiple virtual machines. There are few policies in vmware load balancing . We will take one by one and lets have a look.

Route based on originating virtual port ID



In this vswitch I have two nics allocated.

And I have three virtual machines as bellows



Server A have one Nic,Server B have two Nics & Server C have one Nic.

Route based on originating virtual port ID works like round robin. Server A nic will be use physical vmnic4 for passing the traffic.

Server A first nic will be use vmnic5 and second nic will be use vmnic4

Server C have only one nic and it will use vmnic4.

In this load balancing mechanism it doesn’t measure any other things. That is the main disadvantage of this, but we don’t have to do any modifications to the physical network environment.

Route Based on IP Hash

In this scenario the vswitch select the uplink depend on the source & destination IP address.

There is some calculation happening on this and its uses XOR operations. Based on that it will select the uplink vmnic.

But we need to configure Ether channel or same kind of a features on our physical switches. An ether channel team multiple network adapters in to a one logical unit.

In this method we can get higher throughput and it will distribute traffic more than Route based on originating virtual port ID.

But in this method we need to configure physical switches also. Troubleshooting process also bit complex.

Route Based on MAC hash,

In this method vswitch will select the vnic depend on the mac address. There is some calculation use to select the vmnic. Since mac address is not changing, virtual machines will use same uplink. Also we don’t have to configure our physical switches.

But in this method it cannot detect the actual load of the uplink.

Router based on physical NIC load

In this method vswitch use uplinks load balance to select the vmnic for virtual machines. This based on originationg virtual port. Vswitch check all the uplinks every 30 seconds and if theload exceed 75% it will move the ports of some virtual machines(Highest i/o) to the different uplink/s.

Actually this is the real load balancing, but we need to have vmware distributed switch for this. Which means we have to have vmware enterprise plus license.

Use explicit failover order.

This is not a load balancing mechanism. Vswitch select first active uplink in this list and it will follow the failover order.


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