www.ijecs.in International Journal Of Engineering And Computer Science ISSN:2319-7242 Volume 6 Issue 4 April 2017, Page No. 20806-20808 Index Copernicus value (2015): 58.10 DOI: 10.18535/ijecs/v6i4.01 Preeti P. Thakre, IJECS Volume 6 Issue 4 April, 2017 Page No. 20806-20808 Page 20806 Optimization of Migration Time affected storage overheads during VM Live Migration using Network Attached Storage device Preeti P. Thakre 1 , Vaishali N. Sahare 2 1 Department of Computer Science and Engineering, G. H. Raisoni Institute of Engineering and Technology, RTMNU University, Nagpur, Maharashtra preetithakre28@gmail.com 2 Department of Computer Science and Engineering, G. H. Raisoni Institute of Engineering and Technology, RTMNU University, Nagpur, Maharashtra vaishali.sahare@raisoni.net Abstract: Cloud computing has grown in relevant amount from recent years by inheriting a key feature of server virtualization which is the live migration of virtual machines(VMs). This technique mainly used in datacenters in order to provide cloud services without letting servers down by allowing a virtual machine from one system to another with minimum service interruption. Due to limited available network bandwidth, the network traffic get increases due to large amount of storage data which lead to create overheads during migration and hence increases migration time. This paper focuses on such type of duplicated data which consumes only unnecessary shared network bandwidth, increases migration time during live VM Migration and provide optimized solution using proposed scheme with the help of Network Attached Storage Device (NAS). Keywords: Cloud Computing, Virtual Machine, Live Migration. I. Introduction In cloud computing, the technology that are acceptable to provide virtualized view of physical resources (like for starting a VM) and providing services such as live migration by accommodating a number of virtual machines which refers to term known as Virtualization. Virtualization has become an integral component of the modern data center. It uses software to simulate the existence of hardware and create a virtual computer system. Doing this allows organization to run more than one virtual systems and applications on a single server. This can provide economies of scale and greater efficiency[6]. Live migration is a technology used by administrators to take a host offline for maintainence or upgrading without it. Live migration is mainly used in datacenters for various purposes such as freeing up resources for save power, resource sharing and system maintainence. In general, live migration of running virtual machines (VMs) across distinct physical machines (PMs) serves as the milestone for load balancing and power saving in modern datacenters. Live migration of VMs is most promising approach to control performance overhead of PMs. A. VM Live Migration and it's process: Migrating the virtual machine from one physical server to another either within the same computing environment or across different datacenters is known as Live Migration. During VM live migration, a lot of data like CPU state, memory state, storage state and network state of the targeted virtual machine has been migrated via a computer network (LAN or WAN) from one system to another system. B. Phases of Live migration It has two phases a) Pre-copy Migration Phase and b) post- copy Migration Phase as shown in Fig.1. Efficient VMs live migration can achieve effective VM consolidation which is unique feature to reduce the energy consumption of cloud data centers by putting some of PMs in sleeping mode (power saving mode), while focusing on QoS (Quality of Service) objective. In pre-migration, all the memory pages copies from source to the destination. During this process, there can be modification in the memory pages by user or operating system called as dirty pages. These dirty pages transfers until it will not equal to or exceed the modification rate. Once it reached, migration manager will suspend the VM on source, transfer the remaining dirty pages and alternatively, resume the VM on destination machine. Fig.1. Phases of Live Migration Live migration of virtual machine is usually done by suspending VM at the source and resume at the destination after transferring the copied VM states of the VM at the source machine. The time period during which the source VM or domain stops or suspended is known as downtime and the time taken by the VM to migrate along with its states from source to the destination is known as migration time. It takes several iterations about 20-29 iterations and in each last iteration about 40-50 pages dirtied and almost 3 times RAM has been copied which fortunately ranges downtime from milliseconds to seconds on source machine which is comparitively shorter than migration time and downtime of destination machine.