VMK load_Mod panic failed to load module VMFS2

This past weekend I was doing a few memory upgrades when one of the boxes that I was working on decided not to boot up properly. This was a bummer considering that it was 2am.

Networking did not start properly so I was unable to ssh to the box, however I found the above error messages in the vmware kernel log (/var/log/vmkernel), the hostd log (/var/log/vmware/hostd.log) and on the console.

First I needed to verify the modules that started using the esxcfg-module command with the -l switch. Below is the output of this command, as it should appear, however in this case as we found that the vmklinux and the vmfs3 were loaded up fine but there was no vmfs2 module.

esxcfg-module -l
Device Driver Modules
Module         Enabled Loaded
vmklinux       true    true
bnx2           true    true
cciss          true    true
e1000          true    true
lpfc_740       true    true
lvmdriver      true    true
vmfs3          true    true
etherswitch    true    true
shaper         true    true
tcpip          true    true
cosShadow      true    true
migration      true    true
nfsclient      true    true
deltadisk      true    true

vmfs2          true    true

The we checked whether vmfs2 is not enabled by using the "-g" switch to the same command and found it was not set to load at boot. We then set the boot option to true by using the "-s" switch for the "vmfs2". The performed an esxcfg-boot -b and then rebooted the ESX and it booted up fine.