6.7

Table 1‑76. Networking Performance Enhancement Advice
# Resolution
1 Verify that VMware Tools is installed on each virtual machine.
2 If possible, use vmxnet3 NIC drivers, which are available with VMware Tools. They are optimized for high performance.
3 If virtual machines running on the same host communicate with each other, connect them to the same vSwitch to avoid
transferring packets over the physical network.
4 Assign each physical NIC to a port group and a vSwitch.
5 Use separate physical NICs to handle the different traffic streams, such as network packets generated by virtual machines,
iSCSI protocols, vMotion tasks.
6 Ensure that the physical NIC capacity is large enough to handle the network traffic on that vSwitch. If the capacity is not
enough, consider using a high-bandwidth physical NIC (10 Gbps). Alternatively, consider moving some virtual machines to a
vSwitch with a lighter load or to a new vSwitch.
7 If packets are being dropped at the vSwitch port, increase the virtual network driver ring buffers where applicable.
8 Verify that the reported speed and duplex settings for the physical NIC match the hardware expectations and that the
hardware is configured to run at its maximum capability. For example, verify that NICs with 1 Gbps are not reset to 100 Mbps
because they are connected to an older switch.
9 Verify that all NICs are running in full duplex mode. Hardware connectivity problems might result in a NIC resetting itself to a
lower speed or half duplex mode.
10 Use vNICs that are TCP Segmentation Offload (TSO)-capable, and verify that TSO-Jumbo Frames are enabled where
possible.
Network (Mbps)
The Network (Mbps) chart displays network usage for the 10 virtual machines on the host with the most
network usage.
This chart is located in the Virtual Machines view of the host Performance tab.
Table 1‑77. Data Counters
Chart Label Description
<virtual machine> Sum of the data transmitted and received across all virtual NIC instances connected to the virtual
machine.
n
Counter: usage
n
Stats Type: Rate
n
Unit: Megabits per second (Mbps)
n
Rollup Type: Average (Minimum/Maximum)
n
Collection Level: 1 (4)
Chart Analysis
Network performance depends on the application workload and network configuration. Dropped network
packets indicate a bottleneck in the network. To determine whether packets are being dropped, use
esxtop or the advanced performance charts to examine the droppedTx and droppedRx network counter
values.
vSphere Monitoring and Performance
VMware, Inc. 65