FAQ-What is the function of the MTU of an iSCSI host port? How can I change the MTU value

Publication Date:  2015-07-23 Views:  191 Downloads:  0
Issue Description
What is the function of the maximum transmission unit (MTU) of an iSCSI host port? How can I change the MTU value?

An MTU determines the largest packet of data that can be transmitted on a network. Setting a proper MTU value for an iSCSI host port can increase the data transmission rate.

     The MTU is measured in the unit of byte. If the packet to be forwarded is larger than the MTU value, the packet is divided into multiple fragmented packets each of which is smaller than or equal to the MTU. After the fragmented packets reach the destination, they are reassembled into the original packet. If the original packet is larger than the MTU but does not allow fragmentation, it will be discarded.

This section uses the ISM V100R006 as an example to explain how to change the MTU value of an iSCSI host port.

1.  In the navigation tree, choose Device Info > Storage Unit > Ports.

2.  In the function pane, click the iSCSI Host Port tab.

3.  Select the iSCSI host port that you want to modify, and select Modify.
The Modify iSCSI Host Port dialog box is displayed.

4.  Change the MTU value of the iSCSI host port.

     The default value (bytes) of the MTU of an iSCSI host port is 1500, and you can customize a value from 1500 to 9216.
     On the iSCSI Host Port tab page, the MTU of an FCoE port cannot be changed, and the default value is 2500.

5.  Click OK.
The Warning dialog box is displayed.

6.  Read the content of the dialog box carefully and select I have read the previous information and understood subsequences of the operation.

7.  Click OK.
The Information dialog box is displayed, stating "Operation succeeded".

8.  Click OK.