Lost connectivity to the device mpx.vmhba32:C0:T0:L0 backing the boot filesystem

usb_module_not_available_on_esxi_hp_hosts

This issue appeared on HP blade Proliant XL170r Gen9 running ESXi 6.0.0, 4192238.
Make sure that your blades have their firmwares updated to the latest version.
Have a look at iLO self-Test Results :

Before firmwares upgrade :
hpe_ilo_diagnostics_before_firmwares_upgrade

After firmwares upgrade :
hpe_ilo_diagnostics_after_firmwares_upgrade