org.apache.hadoop.hbase.fs

Class HFileSystem

java.lang.Object

FilterFileSystem

org.apache.hadoop.hbase.fs.HFileSystem

public class HFileSystem
extends FilterFileSystem

An encapsulation for the FileSystem object that hbase uses to access data. This class allows the flexibility of using separate filesystem objects for reading and writing hfiles and wals. In future, if we want to make wals be in a different filesystem, this is the place to make it happen.

Field Summary

Fields

Modifier and Type	Field and Description
static Log	LOG

Constructor Summary

Constructors

Constructor and Description
HFileSystem(Configuration conf, boolean useHBaseChecksum) Create a FileSystem object for HBase regionservers.
HFileSystem(FileSystem fs) Wrap a FileSystem object within a HFileSystem.

Method Summary

Modifier and Type	Method and Description
static boolean	addLocationsOrderInterceptor(Configuration conf)
void	close() Close this filesystem object
FSDataOutputStream	createNonRecursive(Path f, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress) The org.apache.hadoop.fs.FilterFileSystem does not yet support createNonRecursive.
static FileSystem	get(Configuration conf) Create a new HFileSystem object, similar to FileSystem.get().
FileSystem	getBackingFs() Returns the underlying filesystem
static FileSystem	getLocalFs(Configuration conf) Wrap a LocalFileSystem within a HFileSystem.
FileSystem	getNoChecksumFs() Returns the filesystem that is specially setup for doing reads from storage.
boolean	useHBaseChecksum() Are we verifying checksums in HBase?

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

public static final Log LOG

Constructor Detail

HFileSystem

public HFileSystem(Configuration conf,
                   boolean useHBaseChecksum)
            throws IOException

Create a FileSystem object for HBase regionservers.

Parameters:

conf - The configuration to be used for the filesystem

useHBaseChecksum - if true, then use checksum verfication in hbase, otherwise delegate checksum verification to the FileSystem.

Throws:

IOException

HFileSystem

public HFileSystem(FileSystem fs)

Wrap a FileSystem object within a HFileSystem. The noChecksumFs and writefs are both set to be the same specified fs. Do not verify hbase-checksums while reading data from filesystem.

Parameters:

fs - Set the noChecksumFs and writeFs to this specified filesystem.

Method Detail

getNoChecksumFs

public FileSystem getNoChecksumFs()

Returns the filesystem that is specially setup for doing reads from storage. This object avoids doing checksum verifications for reads.

Returns:

The FileSystem object that can be used to read data from files.

getBackingFs

public FileSystem getBackingFs()
                        throws IOException

Returns the underlying filesystem

Returns:

The underlying FileSystem for this FilterFileSystem object.

Throws:

IOException

useHBaseChecksum

public boolean useHBaseChecksum()

Are we verifying checksums in HBase?

Returns:

True, if hbase is configured to verify checksums, otherwise false.

close

public void close()
           throws IOException

Close this filesystem object

Throws:

IOException

addLocationsOrderInterceptor

public static boolean addLocationsOrderInterceptor(Configuration conf)
                                            throws IOException

Throws:

IOException

get

public static FileSystem get(Configuration conf)
                      throws IOException

Create a new HFileSystem object, similar to FileSystem.get(). This returns a filesystem object that avoids checksum verification in the filesystem for hfileblock-reads. For these blocks, checksum verification is done by HBase.

Throws:

IOException

getLocalFs

public static FileSystem getLocalFs(Configuration conf)
                             throws IOException

Wrap a LocalFileSystem within a HFileSystem.

Throws:

IOException

createNonRecursive

public FSDataOutputStream createNonRecursive(Path f,
                                             boolean overwrite,
                                             int bufferSize,
                                             short replication,
                                             long blockSize,
                                             Progressable progress)
                                      throws IOException

The org.apache.hadoop.fs.FilterFileSystem does not yet support createNonRecursive. This is a hadoop bug and when it is fixed in Hadoop, this definition will go away.

Throws:

IOException