Package org.apache.hadoop.hdfs
package org.apache.hadoop.hdfs
A distributed implementation of FileSystem. This is loosely modelled after
Google's GFS.
The most important difference is that unlike GFS, Hadoop DFS files have strictly one writer at any one time. Bytes are always appended to the end of the writer's stream. There is no notion of "record appends" or "mutations" that are then checked or reordered. Writers simply emit a byte stream. That byte stream is guaranteed to be stored in the order written.
-
ClassesClassDescriptionA simple wrapper around
UTF8.This class contains constants for configuration keys and default values used in hdfs.Represent one of the NameNodes configured in the cluster.Comparator for sorting DataNodeInfo[] based on decommissioned and entering_maintenance states.Comparator for sorting DataNodeInfo[] based on slow, stale, entering_maintenance, decommissioning and decommissioned states.DtFetcher is an interface which permits the abstraction and separation of delegation token fetch implementaions across different packages and compilation units.PolicyProviderfor HDFS protocols.Create proxy objects to communicate with a remote NN.DtFetcher for SWebHdfsFileSystem using the base class HdfsDtFetcher impl.DtFetcher for WebHdfsFileSystem using the base class HdfsDtFetcher impl.