Logical Machine Migration

Logical Machine Migration moves a logical machine including all its processes and its operating system with its states to another machine. While the problems of I/O and inter-process communication remain, the migration of a whole machine makes easier solutions to the following topics possible:

Shared Memory:

all processes sharing memory migrate with their shared memory segment to a new machine.

Inter-process communication:

As long as a group of processes on a single logical machine communicates exclusively to processes within itself, there is no residual dependency in message passing between these processes.

Operating system states:

Most of the operating system states concerning the processes on the logical machine are contained within the logical machine.

Machine independence:

A process usually is written to execute on a specific hardware platform. A logical machine could easily be interpreted by the LMM and thus, logical machines are not necessarily bound to the same CPU type but could instead migrate to different hardware platforms.

Efficiency:

if a group of processes on the same logical machine is to be migrated, logical machine migration performs a single migration while process migration has to perform several migrations. Thus, the logical machine migration has less overhead when multiple processes are moved.

On the other hand, moving a logical machine including its operating system involves the overhead of transferring the operating system with every migration. This overhead suggests that logical machine migration might not be the best choice for load-balancing in distributed systems where a permanent sequence of migrations occur.