Research On Key Technologies And Performance Evaluation Of Virtual Network Storage System

The intensive impetus of storage demand in whole world has driven the evolution ofcomputer storage. The gradual development of computer storage is from simple and singlestorage devices such as disk drive, tape drive, RAID to storage network system.Complexities of storage system architecture and data management make the data storage,management and maintainability more and more intricate. The traditional network storagesuch as NAS and SAN has its merit and deficiency respectively. Therefore, we haveexplored the virtual network storage system to consolidate the file-level storage deviceand the block-level storage device. We investigated the system architecture, global dataorganization, key technologies on virtual storage file system, I/O pattern and the effect ofdata assignment on system performance. Based on the introduction of the storage system and storage virtualization technology,we discussed the storage demand and the evolution of the role of storage. We alsoanalyzed the evolution of storage system, i.e. the variety from traditional single device tonetwork storage and virtual storage. Moreover we expounded the main conception andspecific technology of virtual storage, its realization level and model, researchmethodology and status in quo of research. At last, we illuminated the researchsignificance, main content and the sustentation fund. Until now, there is little principle and systemic analysis to virtual technology. Westudied the basic design theory, summarized a sum of promiscuous glossary andterminologies, and gave the concept of virtual handling and virtual storage node. Theabstract structure of virtual network storage system and one of partition methods of storagespace were defined. We also described the logical structure and its virtual realization of threenodes so as to provide the theory foundation and technology repertory to further research. The complex virtual network storage system needs global data and resourcemanagement. Compared with the attributes of traditional file system and network storageoriented distributed file system, we have designed virtual storage file system (VSFS)based on the parallel I/O to realize consistent virtual global name space. VSFS can alsomanage the whole device resources, and provide a lightweight class name service and IIImultiple strategy access patterns. At the same time, to solve the data consistency problemof heterogeneous storage system, we have adopted the two-level lock mechanism includethe file lock and segment lock. We also have researched the file encrypts in VSFS, the testresults show that its performance decreases very little than NFS. Based the analysis on system physical architecture, logical architecture and I/O accesspattern, we made a study of system self-adaptability, presented a share hash algorithm basedon resource capacity. When the num of disks or the disk capacity changed, share hashalgorithm can provide good data assignment and low computing complexity, better loadbalance and self-adaptability. Further more, we emphasized the effect of parallel dataplacement algorithm on system I/O performance in virtual network storage environment. Webrought forward a self-adaptive data striping algorithm that can decide the stripingfrequency based on the performance of virtual node. The test results show that self-adaptivedata striping algorithm has better performance than traditional round-robin algorithm. The structure, protocol and I/O pattern are more complex than the traditional hostattached storage. There are many factors that can affect the I/O performance of networkstorage system. With the fundamentals of stochastic Petri net (SPN), we set up a generalSPN model to depict connection and disconnection of I/O request. Therefore, we putforward the relations of request response time with system workloads, network bandwidthand node performance. Afterward, we established the parallel I/O SPN of network sto...