Disk I/O Bandwidth Allocation Mechanism Of Virtual Machines

With the continuous development of computer hardware technology and thematurity of virtualization technology, a growing number of companies and enterprisesadopt virtualization technology as a resource management solution to improve theutilization and reusability of servers. When multiple VMs (virtual machines) and morekinds of complex applications run on a single physical machine, how to improve theperformance isolation of these VMs and guarantee quality of service will be avirtualization technology topic. On this basis, we propose a VM disk bandwidthallocation method on Xen virtualization platform. According to service priority andweight, our method achieves the system bandwidth proportional allocation among VMs.Disk bandwidth allocation system is designed as a kernel module in backend driverof Xen’s frontend backend driver model, adding control policy in Xen’s native I/Oprocess. The method consists of two parts: the VM bandwidth control system andprediction system. The VM bandwidth control system is mainly responsible for managingand scheduling I/O requests, determine I/O request’s service order. The system modifiesToken Bucket algorithm that is commonly used in network traffic control, adding apublic token bucket. Disk access privilege of each VM is determined by the amount oftokens its bucket has. The adoption of public bucket is to solve the system sparebandwidth sharing among the VMs. Bandwidth demand prediction system is mainlyresponsible for assisting the bandwidth control system more accurately assigningbandwidth, with providing real-time bandwidth demand of each virtual machine.From the final test results, our system works well on function and performance field,achieves disk bandwidth proportional allocation among VMs, and effectively improvesperformance isolation between VMs and the quality of I/O service for specific VM.