如何从MySQL迁移到Cassandra

I had a relational database, that I wanted to migrate to cassandra. Cassandra's sstableloader provides option to load the existing data from flat files to a cassandra ring. Hence this can be used as a way to migrate data in relational databases to cassandra, as most relational databases let us export the data into flat files.

sqoop gives the option to do this effectively. Interestingly, DataStax Enterprise provides everything we want in the big data space as a package. This includes, cassandra, hadoop, hive, pig, sqoop, and mahout, which comes handy in this case.

Under the resources directory, you may find the cassandra, dse, hadoop, hive, log4j-appender, mahout, pig, solr, sqoop, and tomcat specific configurations. For example, from resources/hadoop/bin, you may format the hadoop name node using ./hadoop namenode -format
as usual.

Download and extract DataStax Enterprise binary archive (dse-2.1-bin.tar.gz). * Follow the documentation, which is also available as a PDF. * Migrating a relational database to cassandra is documented and is also blogged. * Before starting DataStax, make sure that the JAVA_HOME is set. This also can be set directly on conf/hadoop-env.sh. * Include the connector to the relational database into a location reachable by sqoop. I put mysql-connector-java-5.1.12-bin.jar under resources/sqoop. * Set the environment $ bin/dse-env.sh * Start DataStax Enterprise, as an Analytics node.
$ sudo bin/dse cassandra -t
where cassandra starts the Cassandra process plus CassandraFS and the -t option starts the Hadoop JobTracker and TaskTracker processes. if you start without the -t flag, the below exception will be thrown during the further operations that are discussed below.