Hbase Basic Prerequisites

Table 2. Java

HBase Version	JDK 6	JDK 7	JDK 8
1.0	Not     Supported	yes	Running with JDK 8 will work but is not well tested.
0.98	yes	yes	Running with JDK 8 works but is not well tested. Building with JDK 8 would require removal of the deprecated remove() method of thePoolMap class and is under consideration. See HBASE-7608 for more information about JDK 8 support.
0.96	yes	yes	N/A
0.94	yes	yes	N/A

Table 3. Hadoop version support matrix

	HBase-0.92.x	HBase-0.94.x	HBase-0.96.x	HBase-0.98.x (Support for Hadoop 1.1+ is deprecated.)	HBase-1.0.x (Hadoop 1.x is NOT supported)
Hadoop-0.20.205	S	X	X	X	X
Hadoop-0.22.x	S	X	X	X	X
Hadoop-1.0.x	X	X	X	X	X
Hadoop-1.1.x	NT	S	S	NT	X
Hadoop-0.23.x	X	S	NT	X	X
Hadoop-2.0.x-alpha	X	NT	X	X	X
Hadoop-2.1.0-beta	X	NT	S	X	X
Hadoop-2.2.0	X	NT	S	S	NT
Hadoop-2.3.x	X	NT	S	S	NT
Hadoop-2.4.x	X	NT	S	S	S
Hadoop-2.5.x	X	NT	S	S	S

4.1.6.

An HDFS datanode has an upper bound on the number of files that it will serve at any one time. Before doing any loading, make sure you have configured Hadoop’s conf/hdfs-site.xml, setting thedfs.datanode.max.transfer.threads value to at least the following:

<property>
  <name>dfs.datanode.max.transfer.threads</name>
  <value>4096</value>
</property>

Be sure to restart your HDFS after making the above configuration.