Research On High Availability Of Distributed File System

The High Availability issue is an important research topic in distributed file systems. Till now,we are short of some qualitative and quantitative analysis method on the high availability researchesof distributed file systems, and many systems are implemented only for the requires of some certainapplication (such as the high availability of Disk Access). We are now in serious need ofcorresponding qualitative theories to instruct us to resolve the following problems: In what degree ahigh available distributed file system should be implemented for some kind of application? Howshould we use the relative key techniques to implement a high available distributed file system?Because we cannot do the quantitative analysis for the degree of availability in software systemlike hardware system, this dissertation does some researches and analysis on the distributed filesystem's high availability issue from a point of qualitative view. Based on the apply mode ofdistributed file system, we did some clustering analysis for the factors which will influence the highavailability issue. Based on the failure and restoring factors, we defined the high availability indistributed file system, and constructed a qualitative analytical model for high availability issue indistributed file system—DFS_HAL ( Distributed File System High Availability Level ) model.After constructing the DFS_HAL model, we integrated it with the implementation techniquesof distributed file system, and by adopting the matrix analytical method, we researched the keyimplementation techniques of high available distributed file system on the conditions of differentapplication requirement. We put emphases on the research of DSR_T ( Distributed State RecoveryTechnology ) and CFS_T ( Continuous File Service ) techniques in DFS_HAL model, put forwardthe transfer-controlling policy in DSR_T, sufficient conditions to satisfy service continuity, and theheuristic requesting algorithm of meta data operation in CFS_T.As a actual application of DFS_HAL model, we present the design and implementationtechniques of the high availability system of Dawning cluster file system-DCFS, describes methodto assure the structural consistency of distributed file system by using the redundant memoryrecording mechanism.The crucial contributions are as follows:1 Based on the apply mode, the failure and restore factors of distributed file system, for the firsttime, we put forward a qualitative analytical model for high availability issue in distributed filesystem—DFS_HAL model.2 Based on the DFS_HAL model, and integrated it with the implementation techniques ofdistributed file system, by adopting the matrix analytical method, we discussed the keyimplementation techniques of high available distributed file system, which works as instructions forimplementation of high available distributed file system.3 Put forward the transfer-controlling policy in DSR_T technique.4 Put forward sufficient conditions to satisfy service continuity and the heuristic requesting...