vmware virutal machines nics

[ful56_uk]

hi guys

i have a virutal machine i would like to get more bandwith to. the host already have a trunk to our hp core switch and the virtual machine has one NIC. The os is 2008 r2.

Mark

[PiqueABoo]

VMWare what?

Based on experience with Workstation I believe you get as much bandwidth as the host can provide regardless of what the virtual NIC in the VM says e.g. VM <-> VM bandwidth which essentially just travels through memory rather than down a wire can be very zippy. I don't know about bigger VMWare, but I imagine you've got some throttling for the VM bandwidth on a virtual switch (assuming that can be done at all - I haven't got a clue) or the bottleneck is the host bandwidth. When you think it's going slow what does the host and say about network performance? Ditto for the VM? Are you sure the issue is bandwidth and not disk I/O?

[ful56_uk]

its vmware esx 3.5, i was just thinking i have a rather large file server so i thought if i added another nic it would help things along a bit better

[apaton]

To get the best network performance out of VMware for Gigabit.

1. Use a quality INTEL NIC's, TSO & Check Sum offload
2. Install VMtools
3. Change VM hardware to use Enhanced VMXnet
4. Use dedicated vSwitch for VM, don't share with VMkernel or Service Console

Don't be tempted to use Jumbo Frames for a file server, not all clients and edge switches will have Jumbo Frame support.

[apaton]

In my previous post I recommended a good Intel NIC, an example of such cards can be found here IBM Redbooks | Intel Ethernet Dual Port and Quad Port Server Adapters for IBM System x

[ful56_uk]

Why use the vmxnet nics for the virtual servers

[apaton]

Performance/efficiency - but many not be seen in every user case.

Enhanced vmxnet driver provide Windows & Linux support for features like TCP Sequence Offload.
If you want to use Jumbo Frames, then you have to use either Enhanced vmxnet or vmxnet3.


Andy

[bio]

hi guys

i have a virutal machine i would like to get more bandwith to. the host already have a trunk to our hp core switch and the virtual machine has one NIC. The os is 2008 r2.

Mark

The question is: The VM is connected to a Vswitch. Does this vswitch have 2 nics connected to it ? if so then the VM can theoritically grab the bandwidth of the entire trunk. So no need to add an extra NIC to that VM.

bio..