MTU 9000 ping not working (VMWare/Server 2003)

RobertKaucher

I have a VMware host attached to an iSCSI SAN. I'm attempting some performance testing and I am configuring the system to allow Jumbo Frames. I have created a virtual switch for the storage network and have the proper MTU configured on the VMware system (NICs/vSwitch) as well as on the physical switch and the storage server. There are two VMs where I am testing iSCSI performance. One is Server 2008 R2 one is Server 2003 R2 (x86) I can perform pings with 9000 bytes to and from the ESXi host and storage server. I can Perform pings of 9000 bytes to and from the Server 2008 R2 VM and the storage server/ESXi host.

I am unable to ping using anything over 1500 bytes on the Server 2003 R2 system. I have checked everything I can imagine and cannot think of what might be causing the problem. I used DrTCP to configure the MTU on the VM, ensured that the NIC is VMXNET 3 and Jumbo Frames is enabled on the NIC. It is connected to the storage network.

Any ideas?

MentholMoose

Check the Advanced tab on the vmxnet3 driver properties in Device Manager. There is an option for jumbo frames.

RobertKaucher

Already done. It was one of the first things I checked as this was my second time configuring it on a VM.

MentholMoose

Are you only using one vSwitch for all the VMs? If not, make sure to enable jumbo frames on every vSwitch.

RobertKaucher

1 vSwitch dedicated to the storage network. 2 teamed NICs.

Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch1       64          6           64                9000    vmnic2,vmnic3
  PortGroup Name      VLAN ID  Used Ports  Uplinks
  Storage Network     0        1           vmnic2,vmnic3
  VM Storage Network  0        2           vmnic2,vmnic3

~ # esxcfg-vmknic -l
Interface  Port Group/DVPort   IP Family IP Address                              Netmask         Broadcast       MAC Address       MTU     TSO MSS   Enabled Type
vmk0       Management Network  IPv4      10.1.46.194                             255.255.255.0   10.1.46.255     00:22:19:24:14:a9 1500    65535     true    STATIC
vmk1       Storage Network     IPv4      172.16.1.3                              255.255.255.0   172.16.1.255    00:50:56:7c:8d:ba 9000    65535     true    STATIC

MentholMoose

Try adding another NIC to the 2003 machine besides a vmxnet3. Maybe it's a driver problem with vmxnet3 on 2003 32-bit.

RobertKaucher

I just tried the VMXNET 2 (Enhanced), disabled the original NIC, and it did not work either. Really we will only be using Server 2008 R2 systems, so it may not matter. But I do not like not being able to give an answer to a question I may be asked.

EDIT: I've given up on this, so don't anyone stress about figuring it out. If I find an answer I will post back.

MentholMoose

Yeah that is annoying. Unfortunately I don't have any other suggestions right now. Hopefully someone else can help.