MapReduce - Hadoop: The Definitive Guide - page 62

Table 3-1. Hadoop filesystems

Filesystem URI
scheme

Java implementation (all under
org.apache.hadoop)

Description

Local A filesystem for a locally

connected disk with client-
side checksums. Use
RawLocalFileSystem for
a local filesystem with no
checksums. See
LocalFileSystem .

file fs.LocalFileSystem

HDFS Hadoop's distributed filesys-

tem. HDFS is designed to
work efficiently in conjunc-
tion with MapReduce.

hdfs hdfs.DistributedFileSystem

WebHDFS webhdfs hdfs.web.WebHdfsFileSystem A filesystem providing au-

thenticated read/write access
to HDFS over HTTP. See
HTTP .

Secure
WebHDFS

The HTTPS version of We-
bHDFS.

swebhdfs hdfs.web.SWebHdfsFileSystem

HAR A filesystem layered on an-

other filesystem for archiv-
ing files. Hadoop Archives
are used for packing lots of
files in HDFS into a single
archive file to reduce the na-
menode's memory usage.
Use the hadoop archive
command to create HAR
files.

har fs.HarFileSystem

View A client-side mount table for

other Hadoop filesystems.
Commonly used to create
mount points for federated
namenodes (see HDFS
Federation ) .

viewfs viewfs.ViewFileSystem

FTP A filesystem backed by an

FTP server.

ftp fs.ftp.FTPFileSystem

S3 A filesystem backed by

Amazon S3. Replaces the

s3a fs.s3a.S3AFileSystem