Optimization Technique Of Block Device Access In Xen Virtual Machine

As an instrument of electronic services, the number of server machines is increasingin recent years. Virtualization provides an excellent way of getting the most out of existinghardware while reducing costs on both money and energy. In a virtualized environment,multiple virtual machines are running simultaneously, and the workloads of storage I/Oincrease heavily, which caused performance bottlenecks become more prominent.To improve the storage performance, we discussed the efficiency of block device thatis the most common storage devices in Xen virtualization platform. Analysis found thatalthough multiple processes are working simultaneously during the storage accessing, thefactors as lock mechanism and unbalance workload have blocked the accessing to serialexecution. Therefore, we increased the processing thread, to optimize the single-channelaccessing to dual-channel. AS speed is not the only factor causing storage bottlenecks,variation needs of workloads and services in each virtual machine are unpredictable andaffect the storage performance significantly. A highly efficiency storage also needseffective scheduling mechanism to satisfy the need of virtual domains. This paper presentsa virtual block device bandwidth splitter, to enhance the resources allocation in Xen,which could adjust the bandwidth of storage I/O in each domain to process more IOrequests and guarantee the quality of storage accessing.Results show that storage performance increases by17%on read and14%on writethrough the dual-channel improvement. And bandwidth allocation could allocate thehardware resources dynamically to keep the reservation bandwidth of each guest domainand maintain stable services.