Home > Workload Solutions > Oracle > Best Practices > Intel-Based Oracle Best Practices on Dell PowerEdge R740 and PowerMax 2000 > Network Best Practices > Day One Best Practices > Networking: Maximum Transmission Unit
The Maximum Transmission Unit (MTU) is the largest packet or frame size that can be sent over the network. In this best practice, the MTU size is adjusted to support a larger packet size.
Category | Networking |
Product | VMware vSphere ESXi VMkernel |
Type of best practice | Performance Optimization |
Day and value | Day 1, Highly Recommended |
Overview
Adjusting the MTU for a larger packet size can improve network efficiency as more user data can be communicated in one packet. Other benefits of a larger MTU include:
To implement a larger MTU size, we modified VMkernel settings from the default MTU size of 1,500 to a size of 9,000 for vMotion.
Recommendation
To test the MTU size of 9,000, the database was running an OLTP workload while the virtual machine was moved using vMotion to another server. We captured the time to vMotion the server as well as New Orders per Minute (NOPM) and Transactions per Minute (TPM) for analysis. Increasing the MTU size showed significant gains for these metrics:
A larger MTU size of 9,000 reduced the time to complete moving the database with an active workload compared to the default MTU size of 1,500. This impressive time-saving function led us to label this best practice as a Day 1, Highly Recommended procedure.
NOPM and TPM also increased, but not as substantially as the vMotion time savings. The overall benefit of this best practice is that database performance has greater consistency during vMotion with a substantial time-saving in moving the database.
Implementation Steps
Process to configure MTU size = 9000 for vMotion network:
. 3. Under VMkernel adapters, select the Motion network and click Edit
4. On the Edit Settings, Under VMkernel port settings, change the value of MTU from 1500 to 9000.
5. Click OK to save the change.
6. Repeat the same steps above on another host.