The Design And Implementation Of Virtual Machine Cluster System Supporting Multi-level Image

With the development of hardware-assisted virtualization technology, the operating efficiency of virtual machines could rival with that of physical machine. On this basis,high-performance servers with the application of system virtualization could provide a service system featured with high availability, high reliability, maintainability, sound security isolation and high usage of hardware. In spite of the advantages over the former ones, the new system needs further improvement after the study of the mainstreamed virtual machines and Open Stack, a management platform of virtual machines. With this regard, we have proposed the following problems.1) Existing cloud computing platforms could only provide the users with fundamental virtual machine images which merely include primary operation system. This mechanism is both time-consuming in the installation of software, and space-consuming since it's incapable of sharing software among different users.2) Although Open Stack provides different snapshot schemes for various storage systems, it's still time-consuming to make a full snapshot in a file based storage system.3) In some scenarios, multilevel snapshot brings about performance loss in existing KVM systems.We have put forward the following methods to solve these problems.1) A novel multilevel image management system has been set up under the mechanism of redirect-on-write in KVM, which not only maximizes the sharing of operating system and software among block devices, but also allows for user's customization of operating system and software.2) In the new image management system, the application of redirect-on-write has improved the primary Open Stack, which has decreased the time of making a snapshot in a file based in a file storage based storage system.3) Considering the performance loss of redirect-on-write brought by multilevel snapshot in KVM, this paper has proposed a new design of disk drive based on global Bitmap table t, which has solved the problem of performance decline of virtual machines while accessing multilevel images.