A computer server system comprises a communications module; a processor coupled with the communications module; and a memory coupled to the processor and storing processor-executable instructions which, when executed by the processor, configure the processor to obtain an indication of scheduled access to a first node class of a shared resource; determine that a second node class of the shared resource is available; and schedule access to the second node class of the shared resource in place of the scheduled access to the first node class of the shared resource.