Abstract: Methods are provided comprising: mapping a portion of a local primary memory to an address space of a virtualization instance at a client device, wherein the address space is addressable by a processor of the client device, and wherein the virtualization instance is executed via the processor of the client device; mapping a first portion of external memory to the address space, wherein the external memory is memory that is external to the client device but treated as primary memory at the client device, and wherein a second portion of the external memory is not in any address space addressable by the processor of the client device; providing a performance indication data structure indicating a performance difference between the portion of the local primary memory mapped to the address space and the first portion of external memory mapped to the address space; and causing data to migrate between the external memory and the local primary memory based on the performance indication data structure by the virtualiz