IO QoS: A New Disk I/O Scheduler Module with QoS Guarantee for Cloud Platform

It´s believed that cloud computing is another great change after previous C/S architecture revolution in computer science area. Disk I/O resource is the importance one of all resources under cloud computing environment. An effective disk I/O QoS system will gain big profit for cloud service providers, cloud users and end users. There are many challenges to face while designing and implementing a disk I/O QoS scheduling system, such as high performance, flexible administration, compatibility, etc. We analyze theories and tools of QoS control, build a proper model and provide a module which can meet our demands. Finally we achieve this goal by referring to mechanism of device-mapper in Linux kernel. To interactive with other part of the system, we modify xend and libvirt to support relevant interfaces with QoS parameters. Our proposal module is evaluated by FIO tool and results imply that the loading of our QoS module only lead to performance loss within 1 % on our testbed.