 Hello everyone, myself is Supriyambarkar from Walshchand Institute of Technology, Sallapur. Today we are going to discuss a topic on VM migration technique that is virtual machines migration techniques. The learning outcome of this topic at the end of this session students will be able to learn the different virtual machine migration techniques also students will be able to identify the various stages of live migration mechanism. Now, first we will see what do you mean by the virtual machine. So, a virtual machine is an emulation of a particular physical system. Virtual machines are often referred to as a guest while the physical machine they run on is referred to as a host. So, virtualization makes it possible to create multiple virtual machines. So, each with their own operating systems and applications on a single physical machine. So, virtualization makes it possible with the help of virtual machines. Now, first we will see the migration concept. So, this diagram shows us the conceptual representation of a virtual machine's migration from host one or host A to another host. So, virtual machine migration might be defined as the virtual machine which is temporarily stopped, snapshot it, moved and then resume on a new host machine. So, in such a way migration has been held from one host to the new host in such a way in this diagram we are able to see the VM is migrated from one host to the another host. Now, we will see the technique in terms of the virtualization or in terms of the virtual machine. So, it is a process of moving a virtual machine from one host server or storage location to the another. So, in this process all key machine components such as CPU, storage, disk, networking, memories are completely virtualized and it is facilitating the entire state of virtual machine to be captured by set of easily moved data files. So, this technique having its own importance. Now, we will see the different types of virtual machine migrations are available. First reason live or hot migration, second reason regular or cold migration, third is a live storage migration. The details we will see in the next slide. First we will see the live migration technique which is also called as a hot or a particular real time migrations. So, it can be defined as the movement of a virtual machine from one physical host to the another while being powered on. So, this is an important point. So, in this migration we can also use for the load balancing purpose in which the work is shared among the different computers the one of the advantage or the having advantage in terms of the it is a fact that it facilitates the proactive maintenance in case of a failure. So, it is having an importance in terms of the advantage. The live migration mechanism we will see one of example of this particular mechanism how memory and virtual states are being transferred through the network or from host A to the host B. For an example, I am going to explain the Zain hypervisor which is an example for this particular live migration mechanism. So, this diagram shows us one of the mechanism which we want to call as a live migration. Here we are having a different stages of this migration, stage 0, 1, 2, 3, 4, 5. The naming has been allocated for the stages. For stage 0, we can call as in a pre-migration stage which is an active virtual machine exists or present on a physical host machine A. Then in a stage 2, when the reservation stage we want to see which will be comes after the stage 0, it is a request issued to migrate an operating system from host A to host B. So, initialization of a container on the target host has been done in the stage 1. Now, we are in a stage 2 which we want to call as an iterative pre-cropy. During the first iteration, all the pages are transferred from host A to the host B and after subsequent iterations copy only those pages which are tied during the particular previous phase of the transfer. So, this is an iterative pre-copy stage. Then in stage 3, stop and copy stage, here the suspended the running operating system instance at host A and host A's network traffic is redirected to host B and in terms of this CPU state and any remaining inconsistent memory pages are then transferred. So, in this way in the stage 3, the end of this stage there is an consistent suspended copy of a virtual machine at both A and B host are allocated and the copy at A considered primary and which will be resumed in the case of any failure occurs. So, this is all about the stage 3. Now, we will discuss the stage 4 which we want to call as a commitment stage. Now in this stage, host B indicates to host A that it has successfully received a consistent operating systems image and host A acknowledges this type of message as a commitment of the migration transaction. After this host A may now discard the original virtual machine and now the host B becomes the primary host. So, this is for the stage 4. Now, we will see the last stage that is in stage 5 which we want to call as an activation stage. In this stage, the migrated virtual machine on host B is now activated. The post migration code run to reattach the devices, drivers to the new machines and advertises mood the IP addresses. In such a way, the stages 0 to 5 are going to held in a live migration mechanism. Now we will see the live migrations effect on a running web server. So, in this diagram which shown us some kind of a notation, some kind of a representation of graphical effects, it is one of the emulation of above migration which we have discussed right now on Apache 1.3 web server which shows the static content at a high rate. The throughput is achieved when continuously serving a single 512 kb files to set up on 100 concurrent clients. So, the server virtual machine has a memory allocation of you can say the 800 MB. At the initial trace, here the server achieves a consistent throughput such as 870 mbps. And here the migration starts at 27 seconds into the trace, but is initially you can say the rate limited to 100 mbps resulting in servers throughput drop to the 765 mbps. So, this initial low rate pass transfer 776 mbps, so the last for the 62 seconds. At this point, the migration algorithm increases its rate over several iterations and finally suspended virtual machine after a further 9.8 seconds. In final phase transfer, the remaining pages and server resumes at full rate after 165 microseconds outage. So, this above simple demonstrate a highly loaded server can be migrated with control impact on live services and short downtime. Now, we will see the list of live migration vendors. First VMware vMotion and second one is on Citrix Zen server ZenMotion, VMware vMotion it allows users to automatically optimize and allocate an entire pool of resources for maximum hardware utilization. And for Citrix Zen server ZenMotion, it balances the particular workload on the virtualized environments. Second type of virtualization migration in terms of the it is regular or cold. It is migration of powered of virtual machines. You have the option of moving the associated disk from one data store to another. The virtual machines are not required to be on a shared storage. So, this is the process for the regular migration. This can be summarized as follows. The configuration files including the nvram file, log files as well as disk of virtual machines are moved from the source host to the destination host associated area. Then the virtual machine is registered with the new host. After the migration is completed, the old version of the virtual machine is deleted from the source host. Now pause the video and write down your answer. Straight the difference between live migration and cold migration. The live migration needs a shared storage for virtual machines in the server's pool, but cold migration does not. And the second one difference, the live migration for virtual machines between two hosts, there would be certain CPU compatibility checks to be applied while in cold migration, this checks do not apply. So, this is the difference. Now, we will see the third migration technique, live storage migration for virtual machine. In this migration, moving the virtual disk or configuration file of a running virtual machine to a new data store without any interruption in the availability of the virtual machines service. This can be head. So, this is for the live storage migration. These are the few references. Thank you, one and all.