The Research Of The Multilevel Quality Of Service Mechanism For Object-Based Storage System

Object-based storage technology which adopts Object interface gives a new chance for Object-based Storage system to support QoS, the extensibility of object makes it easy for client to deliver QoS requirement and OSD to accept and understand QoS requirement. Real-time stream, one type of load supported by Object-based Storage system, has different QoS requirements in different case.Object-based Storage system is needed to provide multilevel QoS mechanismFrom the system perspective, client deliver QoS requirement to Object-based Storage Device(OSD: Object-based Storage Device) and OSD provide multilevel QoS mechanism. From best-effort, OSD meet the QoS requirement well and support different QoS requirements. Making use of (m,k) pattern's character that this pattern can divide real-time jobs into mandatory jobs and selected jobs, considering with storage QoS, (m,k) pattern is combined with Object-based Storage System, then (m,k) pattern-based multilevel QoS mechanism has been put forward in Object-based Storage System. Defining the multilevel QoS mechanism Framework from three aspects: the QoS level definition, the interactive process between client and OSD, the implemention strategy.While implementing the multilevel QoS mechanism, different data copy are needed to be stored in HOSS. The problem of data layout has been solved by horizontal (m,k) model application and longitudinal (m,k) model application in HOSS. According to the strategy of data layout, (m,k) model can be used in data recovery, named (m,k) Recovery Technique. From analyzing the condition of over-loaded, the strategy of request and scheduling has been put forward while HOSS is over-load. The strategy can come true the goal that HOSS services more users in the condition of fixed disk bandwidth. All the strategy has been tested and the test results meet the theoretical analysis.