ESX host tries to read VCMDB device

I have an ESX host that keeps trying to read from VCMDB device.

Vcenter performance metrics are horrible obviously (4000 ms read latency) since it will never actually talk to it.

I have to explain why ESX host is behaving like this just now after months of not reporting any problems.

Is this normal ESX OS behavior?

ESX host is not admin server (No Symcli etc)

This device is controlled by NMP, Powerpath ignores it.

I know I can unmap it from FAs but I want to understand host behavior.

Vsphere 4.1

DMX 4 and Vmax

VCMDB Device 42 is 5.6mb

Thanks !