Package org.apache.hadoop.fs.s3

A distributed, block-based implementation of FileSystem that uses Amazon S3 as a backing store.

See: Description

Class Summary

Class	Description
MigrationTool	This class is a tool for migrating data from an older to a newer version of an S3 filesystem.
S3FileSystem	A block-based FileSystem backed by Amazon S3.

Exception Summary

Exception	Description
S3Exception	Thrown if there is a problem communicating with Amazon S3.
S3FileSystemException	Thrown when there is a fatal exception while using S3FileSystem.
VersionMismatchException	Thrown when Hadoop cannot read the version of the data stored in S3FileSystem.

Package org.apache.hadoop.fs.s3 Description

A distributed, block-based implementation of FileSystem that uses Amazon S3 as a backing store.

Files are stored in S3 as blocks (represented by Block), which have an ID and a length. Block metadata is stored in S3 as a small record (represented by INode) using the URL-encoded path string as a key. Inodes record the file type (regular file or directory) and the list of blocks. This design makes it easy to seek to any given position in a file by reading the inode data to compute which block to access, then using S3's support for HTTP Range headers to start streaming from the correct position. Renames are also efficient since only the inode is moved (by a DELETE followed by a PUT since S3 does not support renames).

For a single file /dir1/file1 which takes two blocks of storage, the file structure in S3 would be something like this:

/
/dir1
/dir1/file1
block-6415776850131549260
block-3026438247347758425

Inodes start with a leading /, while blocks are prefixed with block-.