6.0.1

Table 1‑69. Networking Performance Enhancement Advice (Continued)
# Resolution
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 Rate (Mbps)
The Network Rate chart displays network bandwidth on a host.
The Network Data Transmitted/Received chart for hosts is located in the Home view of the Host
Performance tab.
Table 1‑70. Data Counters
Chart Label Description
Data Receive Rate Rate at which data is received across the top ten physical NIC instances on the host.
This represents the bandwidth of the network. The chart also displays the
aggregated data receive rate of all physical NICs.
n
Counter: received
n
Stats Type: Rate
n
Unit: Megabits per second (Mbps)
n
Rollup Type: Average
n
Collection Level: 3 (4)
Data Transmit Rate Rate at which data is transmitted across the top ten physical NIC instances on the
host. This represents the bandwidth of the network. The chart also displays the
aggregated data transmit rate of all physical NICs.
n
Counter: transmitted
n
Stats Type: Rate
n
Unit: Megabits per second (Mbps)
n
Rollup Type: Average
n
Collection Level: 3 (4)
Chart Analysis
Network performance depends on 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.
If packets are being dropped, adjust the virtual machine shares. If packets are not being dropped, check the
size of the network packets and the data receive and transfer rates. In general, the larger the network
packets, the faster the network speed. When the packet size is large, fewer packets are transferred, which
reduces the amount of CPU required to process the data. When network packets are small, more packets are
transferred but the network speed is slower because more CPU is required to process the data.
NOTE In some instances, large packets might result in high network latency. To check network latency, use
the VMware AppSpeed performance monitoring application or a third-party application.
If packets are not being dropped and the data receive rate is slow, the host is probably lacking the CPU
resources required to handle the load. Check the number of virtual machines assigned to each physical NIC.
If necessary, perform load balancing by moving virtual machines to different vSwitches or by adding more
NICs to the host. You can also move virtual machines to another host or increase the host CPU or virtual
machine CPU.
If you experience network-related performance problems, also consider taking the actions listed below.
vSphere Monitoring and Performance
54 VMware, Inc.