DFS-oriented client persistent caching method and system in global namespace

The invention discloses a DFS-oriented client persistent caching method and system in a global namespace, and belongs to the field of large-scale distributed systems, and the method comprises the steps that a metadata server maintains a view of a global directory tree, all clients share the view, and all the clients can access any file through the view; the client identifies a file needing to be prefetched according to the cache prefetching rule, and migrates the file from the object storage server to the local for persistent caching; when the data volume of the local cache of the client exceeds a cache threshold, the data locally cached by the client is replaced; when the client performs file operation, if the to-be-operated file is cached to the local of the client and the client has thecorresponding operation authority, the locally cached file is directly accessed and the operation is finished; otherwise, the file is remotely accessed in the object storage server through the network and the operation is fi