Design And Optimization Method Of Distributed COW Disk On Network Computing Environment

Since the human society move into the information age, the computing performance requirements continue to increase, the Network-computing mode can fully integrate computing resources to meet the high demands of computing performance, and become a research focus. Under the Network-computing mode,the computing tasks are submitted to the various computing resources(client host), and data (system data and user data) are deployed in the network storage devices, thus achieve the separation of the storage and computation. The system data stored in the storage resources is no longer belong to a particular subject, which can be shared by all hosts in the network computing environment. In this mode, the storage structure and the storage optimization in the network computing environment becomes crucial.The paper aiming to distributed computing and data centralizing storage in large-scale network computing environments and combining sparse and bursting characteristic of COW(copy-on-write) disk storing modified data blocks, presents a distributed COW network disk architecture.In this storage system, shared data centrally stored in read-only disk in the shared source, the client host rewrite the block to shared data is stored in the corresponding distributed COW disk.The system not only achieve the separation of the storage and computation, and further optimize the read and write operations of shared data.This paper is involved in below subject:First, based on the COW (copy-on-write) technology we presents the distributed COW network disk storage model.Combining sparse and bursting characteristic of COW disk storing modified data blocks, the paper detailly describe the distributed COW network drive architecture and it’s read-write mode.The system building process of network computing environments was speeded up by apportioning the aggregation spending that server manages all related COW disks of client hosts to each client host.Second,A improving64bit bitmap compress arithmetic was designed to reduce the size of COW disk’s bitmap, so server disk space was saved and the network communication spending of distributed COW disk was less. The modified prefetching arithmetic based on COW bursting blocks was presented to improve the hit rate of Cache relating with distributed COW disk.At last,the experiments shows that the distributed COW network disk successful realization of the multi-host data shared access under the network computing environment.Experiments on the prototype also show that the distributed COW mechanism can effectively reduce system building latency of multi-client hosts network computing environment based on improving COW bitmap compress and prefetching arithmetic.