This directory contains the hdfs extensions needed to make leveldb store files in HDFS. The hdfs.h file is copied from the Apache Hadoop 1.0 source code. It defines the libhdfs library (http://hadoop.apache.org/common/docs/r0.20.2/libhdfs.html) to access data in HDFS. The libhdfs.a is copied from the Apache Hadoop 1.0 build. It implements the API defined in hdfs.h. If your hadoop cluster is running a different hadoop release, then install these two files manually from your hadoop distribution and then recompile leveldb. The env_hdfs.h file defines the leveldb objects that are needed to talk to an underlying filesystem. If you want to compile leveldb with hdfs support, please set the following enviroment variables appropriately: USE_HDFS=1 JAVA_HOME=/usr/local/jdk-6u22-64 LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$JAVA_HOME/jre/lib/amd64/server:$JAVA_HOME/jre/lib/amd64/:./snappy/libs make clean all db_bench To run dbbench, set CLASSPATH to include your hadoop distribution db_bench --hdfs="hdfs://hbaseudbperf001.snc1.facebook.com:9000"