1. A hyper-converged infrastructure (HCI) system, the HCI system comprising: a pair of physical computing servers coupled to a network, each of the pair of physical computing servers configured to run a respective set of host application instances and to operate an IO (Input/Output) stack; and a set of shared, nonvolatile storage devices coupled to each of the pair of physical computing servers and shared between the pair of physical computing servers, the set of shared, nonvolatile storage devices providing redundant storage of data of the host application instances, wherein each of the pair of physical computing servers is constructed and arranged to (i) receive client requests over the network, the client requests directed to one of the set of host application instances running on that physical computing server, (ii) generate, via operation of that host application instance, IO requests specifying reads and writes of application data, and (iii) process, via the respective IO stack, the IO requests to effect the specified reads and writes of application data in the set of shared, nonvolatile storage devices, wherein the IO stack running in each of the pair of physical computing servers exposes a respective set of host-application-accessible data objects, the set of host-application-accessible data objects built from the set of shared, nonvolatile storage devices, and wherein the HCI system further comprises an administrative server constructed and arranged to provide a system-level view of host-application-accessible data objects across physical computing servers in the HCI system.