Enable Jumbo frame for VM

Question

_{Thursday, October 29, 2015 6:18 PM}

Hello,

I recently enabled jumbo frames inside a virtual machine and enabled jumbo frames on the physical network adapter assigned to that virtual machine. When I try to setup the icsi initiator it becomes unresponsive . When I disable jumbo frames within the VM everything works fine. I enabled jumbo the switch and on the DAS device. 

All replies (10)

_{Monday, November 23, 2015 4:41 PM ✅Answered}

Sorry for the delay.

The following steps are what I did to fix the issue:

1. Disabled jumbo frames from the Microsoft Hyper-V Network adapter properties within the virtual machine. 
2. Rebooted VM
3. Set the jumbo frame to 9000 in the registry for the Microsoft Hyper-V Network adapter. 
4. Rebooted VM

Now I’m able to ping the ISCSI storage server using ping -l 9000 iscsitargetip and the virtual machine is no longer freezing up.

Thank you All for the Help!





_{Thursday, October 29, 2015 6:47 PM}

When you say "*I enabled jumbo the switch and on the DAS device. *" do you mean that you enabled jumbo frames on the physical network switch and on the iSCSI target?  The term 'DAS' has me confused because that has historically meant direct-attached storage, which did not include iSCSI, since that is network attached.

. : | : . : | : . tim

_{Thursday, October 29, 2015 7:36 PM}

you can check before setting up iscsi if the path works with Jumbo Frames.

ping the SAN iscsi target with

ping -l 9000 iscsitargetip

you can modify to see what size of packets your Connection Supports. if the ping Fails at 9000 but works with 1500, id look for where the Jumbo Frames are not configured in the path. if the ping with 9000 sized packets works id check with the san vendor if it Supports Jumbo Frames (ive seen low Budget iscsi Targets having Trouble with Jumbo Frames)

_{Thursday, October 29, 2015 8:22 PM}

Sorry I meant NAS....

_{Tuesday, November 3, 2015 9:34 PM}

I did ping -l 9000 iscsitargetip  from another server that has jumbo frames enabled and it worked. When I try to ping from the Virtual machine it doesn't work, it only work when I ping -l 1500 iscsitargetip 

_{Wednesday, November 4, 2015 2:37 AM}

Hi,

In order to support jumbo frame, you also need to configure on the switch port to support jumbo frame.

You can refer to this guide as reference:- http://windowsitpro.com/windows/q-how-do-i-enable-jumbo-frames

Lai (My blog:- http://www.ms4u.info)

_{Wednesday, November 4, 2015 2:19 PM}

-Hello

I enabled jumbo frames on the Physical network card, the guest network card and the switch that the Host server is connected to.

_{Wednesday, November 4, 2015 2:53 PM}

how about on virtual switch (created from Hyper-V), the one that you bind to VM?

Lai (My blog:- http://www.ms4u.info)

_{Wednesday, November 4, 2015 4:14 PM}



_{Monday, November 9, 2015 3:24 AM}

Hi Leopete,

Have you allowed host to share the external virtual switch? If yes, try to ping -l 9000 iscsitargetip on host.

If possible, delete the virtual switch. Perform the test on host. It could check if Hyper-V virtual network affected the result.

Best Regards,

Leo

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