setting VM nic speeds

[Oli_L]

Is there a way to set the virtual machine's network card connection speed. I hav e looked at the advanced network adapter configuration options but this is not an option.

We do not have enough supply of 1gig network connections to backbone switches. I am thinking if it is at all possible to set up a VSwitch and set the connection to 1gig but have the virtual machines talking to the vswitch at 100mbs rather than 1gig? I can then make sure that VM nic bandwidth capacity does break the band width supply which would be limited to 1gig; ie I could essentially have 10 x 100mbs VM's connected to a 1gig vswitch

TIA

Oli

[bister]

This is done by the VMkernel. There is normally no need to limit the bandwidth of a VM. VMs only use the bandwidth they currently need.

[Oli_L]

Thanks for your answer

I still haven't quite got my answer yet! Are you suggesting that if an intensive application server needed alot of bandwidth it could take upto a 1gig even though my network swicthes can only give me 100meg - if I had a fair few of these servers, imaging servers, mail servers etc then this would produce a bottleneck if I could only provided 100meg

My real question here is what are the best practises to control network traffic within your MV environment if you could only provide a few didicated 1gig ports and others that could only provide 100meg? Is this managed at the VSwicth level? Say create a VSwitch which has dedicated NICS that provide 1Gig and another VSwitch that provided 100meg, therefore allowing for different bandwidths consumptions for VMs?

Hope my question makes sense?!

Oli

[bister]

Oh, sorry, you got me wrong...

Even if the vNIC of the VM shows it's running with 1GBit it will only get a max. of 100MBit when connected to a 100MBit physical NIC. The vNIC always displays 1GBit.

With NICs it is the same as with CPU: A VM will get as much resources as it requests. If multiple VM need the same resource it depends on how much shares are configured for each VM.

You can of course create different groups of vSwitches to provide different bandwidth for your VMs. But I experienced no problems with multiple VMs on 100MBit NICs, as network was never a real issue...

Respectfully,

Christian

[wobbly1]

Oli,

The VMs will only get up to the maximum bandwidth of the physical link between the ESX server and switch. If you do have some bandwidth intensive apps then having seperate vSwitches with a dedicated physical nic may be you best option to prevent bottleneck.

[wobbly1]

The other option may be to create port groups within a vswitch and set different traffic shaping policies for each group

[Oli_L]

ok - the answers here are a great help! Thanks

I was aware about the 1g network connection status that the VMs displays.

I suppose the answer is a mixture of what everyone says. A bit of traffic shaping, vswitch management - VLAN and port groups also come into play.

I know you can get quite smart with how to manage the network traffic. This also goes for memory and CPU - the lot! I had a call open with tech support about how when i start up my VMs they always trigger the memory alarms - their repsonse was this is normal as a VM will get as much resources as it requests and the win2003 is designed to in a way it will take up as much resources as it can when booting?! Even though I had set resource limits.

I suppose I'll just have to get use to some of the 'quirks' ESX has but make sure the thing is logically managed!

I'm just treading carfeully as we also going virtual in a big way and Im currently laying down the foundations!

Thanks for your help - and feel free to share more tips with me! I need 'em