Unable to vmkping from iSCSI jumbo frame enabled VMkernel

Products

• VMware vSphere ESXi

Issue/Introduction

• Cannot perform vmkping to storage array IP address.
• Unable to vmkping from iSCSI jumbo frame enabled VMkernel.
• ESXi host is configured with 3 or 2 VMkernel interface.

Cause

Multiple VMkernel interfaces on the same subnet must have the same configuration for MTU/VLAN to avoid issues. This issue occurs if any one of the VMkernel interface configuration is not identical.

 

For example, when VMKernel interface vmk1 used for Storage Hearbeat is not configured with the correct MTU, running esxcfg-vmknic -l command, you see output similar to:

 

Interface Port Group/DVPort IP Family IP Address Netmask Broadcast MAC Address MTU TSO MSS Enabled Type
vmk0 Management Network IPv4 10.###.###.# 255.255.255.0 10.###.###.255 ##:##;##;##;##;## 1500 65535 true STATIC
vmk1 Storage Heartbeat IPv4 10.###.###.# 255.255.255.0 10.###.###.255 ##:##;##;##;##;## 1500 65535 true STATIC
vmk2 iSCSI1 IPv4 10.###.###.# 255.255.255.0 10.###.###.255 ##:##;##;##;##;## 9000 65535 true STATIC
vmk3 iSCSI2 IPv4 10.###.###.# 255.255.255.0 10.###.###255 ##:##;##;##;##;## 9000 65535 true STATIC

Resolution

To resolve this issue, ensure that the VMkernel interface configuration on the same subnet is identical.

 

Verify VMkernel (vmk) connectivity to the storage target (storage array IP address) using the following command:

vmkping -I vmkX -d -s 8972 x.x.x.x // Where vmkX is the VMkernel created for iSCSI and x.x.x.x is the array IP.

Additional Information

iSCSI and Jumbo Frames configuration on VMware ESXi/ESX