Maximum VM's / NIC

[cbergoo]

We are planning for a disaster recovery scenario and configure our ESX 3 virtual infrastructure servers for it. Our question is how many VM's can I have on one (1) physical NIC?

[Texiwill]

Hello,

The answer to that question really depends on your network traffic. If the NIC is GigE then you should be able to have quite a few, but then again if 2 VMs push 700Mbits per second then you can only fit 2 VMs on one NIC. If you say have VMs that only push 7Mbits per second then you could have 100 VMs before you hit the theoretical max of a GigE network interface.

Best to see what your existing network requirements are and plan using those values. The information is available from the VI Client or by running esxtop from the command line of the Service Console.

Best regards,

Edward

[cbergoo]

Hi,

And thanks.

But I have a follow up question, is there a maximum limit of VMs that could use one physical NIC? We have two 1GB-cards in each ESX-server and are planning to run a maximum of 32 VMs on those two 1GB cards if one ESX-server is broken? I don't think that it is going to be so much load on the NICs but I want to be sure that it will work if I have to move 16 VMs from one server to the other.

Best regards

Claes

[murreyaw]

It should work. As mentioned above, there isn't really a hard limit on how many actual VMs can be on a signle hardware Nic. Nics are cheap. If you have performance problems, go spend a hundred bucks on another one.

[bflynn0]

By default a virtual switch has 56 available ports. So if your VM's all have 1 nic connected you can have 56 VM's per virtual switch. You can change the number of ports on a virtual switch (it requires a reboot of the ESX host though). The maximum number of portsd you can have on a virtual switch is 1016.

Note: the virtual switch that is created during the ESX installation (with the service console assigned) has 24 ports available by default.