Research On Virtual Machine's High-Availability Devices Technologies

With the rapid development of computer hardware, network and system structure, the virtualization technology has already been widely used in some fields, and has shown a new tendency that it has become a new hotspot from server virtualization to memory virtualization, also in the application virtualization.At the same time, virtualization technology in the management, application and security is also facing new challenge. In blade servers, data centers, and other virtual environment, the ability to ensure uninterrupted service is highly demanded, but the ability that protected virtual machine continuous accesses the I/O devices during traditional live VM migration is not enough. As a result, more effective technologies are needed to protect that VM continuous accesses I/O devices during live VM migration.To deal with those problems, this paper designs Device-Agent model that guarantees virtual machine to access continuously I/O devices during live VM migration. Device-Agent model is composed of three major modules, device-agent module, remote access device module and Device dynamic exchange module. Device-Agent module is in charge the I/O transactions and maintaining the states of virtual device during live VM migration. Remote Access Device module makes virtual machines accessing remote I/O devices like locals, thus no longer dependent on SNA in accessing remote I/O devices. Device Dynamic Exchange module enables virtual machine to re-orientation to the physical device dynamically, and improves the availability of VM's device.During live VM migration base on Device-Agent module, the state may be inconsistencies in dealing with the pending I/O transactions. This article uses the SMT and QBM algorithm of uniformity maintenance to solve this problem. The SMT algorithm mainly process the pending I/O transactions of the same length, while the QBM mainly process ones of not the same length.When designing the SMT algorithm, Feature Value and Hasche Search are introduced into algorihm in order to enhance efficiency to carry out it. After SMT algorithm matching operations, the remaining pending I/O transactions will be different from those to be matched in length. Method of moving the whole in QBM algorithm is adopted to do exact matching operation.Based on the analysis above, this article designed Device-Agent architecture based on Xen. By consulting the Xen artchitecture we designed the Device-Agent module, the Remote Access device module and the Device Dynamic Exchange module separately. Finally, the performance evaluation of Device-Agent model is carried out. Tests show that theDevice-Agent model ensures that the I/O services are uninterrupted during live VM migration.This project is supported by 863 Projects: Based on the virtual machine technology commecial high-end blade server system and the virtual personal computer systems of multi-Dom calculation, and NFS projects: The design of the Trusted computing software and environment based on the architecture of the virtual machine.