Abstract
Virtualization technology enables organizations to take the benefit of different services, operating systems, and software without increasing their IT infrastructure liabilities. Live migration of virtual machine is the key features of the virtualization. It allows the administrator to move the virtual machine from one physical machine to another physical machine without any interruption. This technique is widely used for load balancing, server maintenance, and resource consolidation. The virtual machine migration problem consists of four distinct steps. The first step is to select the host from where VM migrated. After selecting, the host next step is to select the VM, which is migrated. The third step is to select the host where the migrated VM will be placed, and the last step is to decide the method, which is used to transfer the VM. This chapter covers all the basic information related to VM migration.
TopVirual Machine Migration
Transferring of a virtual machine from one physical machine (server) to another physical machine is called virtual machine migration. Down time and total migration time are the two metric, which define the effectiveness of the migration algorithms. Downtime is defined as the time for which service of the virtual machine are not available to the user.
Total migration time is time duration between the migrations initiated at the source to the time when the migrated virtual machine gets a consistent state with the original state at the destination. Downtime and total migration time both should be minimum possible for effective migration (SearchServerVirtualization, 2014).
Key Terms in this Chapter
Virtual to Virtual (V2V): Virtual to virtual (V2V) is a term that refers to the migration of an operating system (OS), application programs and data from a virtual machine to another virtual machine. The target can be a single system or multiple systems. V2V can be used to copy or restore files, programs, or OS components to a virtual machine from a different virtual machine.
Hypervisior: Virtualization is implemented through the hypervisor called as a Virtual Machine Monitor (VMM). The Hypervisor is a software layer, which manages all virtual machines and separates the virtual hardware from the actual hardware. Each user has its own virtual machine, which is created based on user requirement. Each virtual machine has its own resources. Number of virtual machines can be run on a single physical machine.
Live Migration: A valuable feature of any hypervisor. Live migration is the movement of a virtual machine from one physical host to another while continuously powered-up. Live migration allows an administrator to take a virtual machine offline for maintenance or upgrading without subjecting the system's users to downtime. It is mainly used for Load Balancing, in which work is shared among computers in order to optimize the utilization of available CPU resources.
Physical to Virtual (P2V): Physical to virtual (P2V) is a term that refers to the migration of an operating system (OS), application programs and data from a computer's main hard disk to a virtual machine or a disk partition. P2V can be done manually by creating a virtual location and then reinstalling the OS, applications, and data on it.