not mandatory。 CarbonData support local file system，HDFS and S3（Huawei OBS）
There are some examples， for example：./carbondata/examples/spark2/src/main/scala/org/apache/carbondata/examples/CarbonSessionExample.scala -- Sent from: http://apache-carbondata-dev-mailing-list-archive.1130556.n5.nabble.com/
