第七讲虚拟化技术第七讲虚拟技术化技术.ppt

* * * * * * “Virtualization technologies will increase the ability to effectively consolidate to larger servers. …Virtualization technologies will also make distributed small servers easier to manage, re-provision and use efficiently.” * * [Click ONCE to show the bullets for each graphic] We typically break describe three key properties of virtual machines that are responsible for their powerful benefits. Let’s examine each one of those properties… The first key property is partitioning. Virtual machines allow a single computer to be divided into separated partitions that can each run an operating system and application stack concurrently. In fact, those virtual machines can be running completely different operating systems and software because they each have their own virtual storage locations, memory spaces and networking interfaces. A component of the VMware virtualization layer called the virtual machine monitor manages the concurrent execution of each virtual machine on the host system hardware. Typically we’d actually see a ratio of about 4 to 8 running virtual machines per physical CPU. The networking and storage features of virtual machines let you use them just as you would real machines in networked configurations or joined together in clusters for high-availability. 2. Our second critical feature is isolation which is critical for safe and reliable server consolidation. VMware Virtual machine monitors use the hardware protection features of the CPU to isolate the virtual machines from each other and the monitor. By basing our isolation on the hardware protection we get very strong isolation. In other words, there is unlikely to be a hole. Each virtual machine is isolated from the host and other VMs, in the sense that it doesn’t share a kernel or processes. In a real environment, what this means is that applications in one virtual machine can encounter viruses or blue screen their operating system, and there is no effect on any other virtual machi