Database Reference
In-Depth Information
Modern 10Gbps and above network adapters include features such as Large Segment
Offload and Large Receive Offload to try and alleviate the overhead of dealing with
many standard-size packets when using a 1,500 byte MTU. However, this doesn't
address the entire overhead, and as a result both source and destination systems
experience lower throughput, higher latency, and higher CPU usage than is necessary.
Using jumbo frames can address these problems and provide the best performance for
high-bandwidth networks and where you are using features such as SQL AlwaysOn
Availability Groups.
Using jumbo frames allows for protocol data units above 1,500 bytes to be transmitted
and received without fragmentation, thereby reducing the total number of packets and the
amount of overall packet processing required to send large amounts of data. The MTU
and jumbo frame size can vary across different network vendors, but they commonly
allow for up to six times the size of a standard-sized packet.
Figure 8.4
displays the throughput and CPU utilization between Windows 2012 VMs on
different hosts when configured with jumbo frames.
Figure 8.4
Virtual network adapter performance with jumbo frames.
Caution
The version of VMXNET3 shipped in VMware Tools as part of VMware
vSphere 5.0 GA had a bug that prevented jumbo frames from working. It is
recommended that you have the latest version of VMware Tools installed, and
