ESXi supports the use of Jumbo Frames with iSCSI and iSER protocols. Jumbo Frames are Ethernet frames with the size that exceeds 1500 Bytes. The maximum transmission unit (MTU) parameter is typically used to measure the size of Jumbo Frames.

When you use Jumbo Frames for iSCSI traffic, the following considerations apply:

  • All network components must support Jumbo Frames.
  • Check with your vendors to ensure your physical NICs and iSCSI adapters support Jumbo Frames.
  • To set up and verify physical network switches for Jumbo Frames, consult your vendor documentation.

The following table explains the level of support that ESXi provides to Jumbo Frames.

Table 1. Support of Jumbo Frames
Type of iSCSI Adapters Jumbo Frames Support
Software iSCSI Supported
Dependent Hardware iSCSI Supported. Check with vendor.
Independent Hardware iSCSI Supported. Check with vendor.
VMware iSER Supported. Check with vendor.

Enable Jumbo Frames for Networking

You can enable Jumbo Frames for ESXi storage adapters that use VMkernel networking for their traffic. These adapters include software iSCSI adapters, dependent hardware iSCSI adapters, and VMware iSER adapters.

To enable Jumbo Frames, change the default value of the maximum transmission units (MTU) parameter. You change the MTU parameter on the vSphere switch that you use for iSCSI traffic. For more information, see the vSphere Networking documentation.

Procedure

  1. In the vSphere Client, navigate to the ESXi host.
  2. Click the Configure tab.
  3. Under Networking, click Virtual switches, and select the vSphere switch that you want to modify from the list.
  4. Click the Edit settings icon.
  5. On the Properties page, change the MTU parameter.
    This step sets the MTU for all physical NICs on that standard switch. Set the MTU value to the largest MTU size among all NICs connected to the standard switch. ESXi supports the MTU size of up to 9000 Bytes.

Enable Jumbo Frames for Independent Hardware iSCSI

To enable Jumbo Frames for independent hardware iSCSI adapters on your ESXi host, change the default value of the maximum transmission units (MTU) parameter.

Use the Advanced Options settings to change the MTU parameter for the iSCSI HBA.

Procedure

  1. In the vSphere Client, navigate to the ESXi host.
  2. Click the Configure tab.
  3. Under Storage, click Storage Adapters, and select the independent hardware iSCSI adapter from the list of adapters.
  4. Click the Advanced Options tab and click Edit.
  5. Change the value of the MTU parameter.
    ESXi supports the MTU size up to 9000 Bytes.