Inventory Service for multiple vCenter Server

Hi,

i´m thinking about a vSphere design option for multiple vCenter.

I´m deploying multiple vCenter Server 5.1 (<10) as a VM. Instead of using one Inventory service per vCenter Server i would like to use a single Inventory instance on a separate VM for all vCenter Server. The VMs are running on a cluster which is configured for HA/DRS.

I wonder whether there would be a disadvantage?