Research On Cluster Oriented Distributed Cache Mechanism

The effieieney of file accessing in cluster file system Plays an important role in the performance of the cluster system. The efficiency of cache is much higher than the disk, if the operation of the document are all read from the cache, it will greatly improve efficiency. MO SIX cluster system performance process migration on the kernel level, and all of the files used by migrated process are just cached on the server side. increased requirements of cache on server side. So, when the server side is busy, the cache on server side need to discard data frequently, and then load new files in. This may lead to the lack of cache on server side, degrade the performance of cluster system. The lack of server cache become a restricted key to cluster system’s efficient. This paper presented the mechanism of distribute cache which is aimed on extending the capability of cache on server side and reducing the time of reading files from disc.This paper analyses the technology of the process migration on MOSIX cluster system and the organization of cache on linux. And then, it suggests the mechanism of distributed cache.The mechanism could collect the cache information at each node in the cluster and migrate cache from high operating load node to the low one. This paper describes the processes of how cache be migrated from server to coorpetate nodes, and the processes of how the cache on server being migrated to cooperative nodes and the procedures on how the server side redirect the request which aimed on file acquiring coming from server side to cooperative nodes, depending on the migrating infromation of distributed cache.This paper redefined the structure of the cache block header depending on the mechanism of distributed cache, and added some properties related to fullfill the request of cache migration. This paper discussed some problems about the mechanism and try to find out a solution to these problems. Including how to store the migrated cache block on coorpetate nodes, how to hit the migrated cache block in cache area on coorpete nodes, how to avoid the same cache block appeared in migration cache area and local cache area at the same time, and how to strcture the cache block in migration cache area. At last, the difference points of the processes of migration cache machanism and original cache mechanism were analyzed. At last, this paper make an analysis about the preconditions under which the mechanism of distributed cache can improve the system performance, summarized the key to the efficiency of migration cache mechanism, and then, make a conclusion about the prerequisite of the situation when the new cache mechanism could enhance the performance of the system depending on the analysis before.