Before starting Hadoop in either pseudo-distributed or fully distributed mode for the first br time, we need to format the HDFS filesystem that it will use. br br This is not a very exciting output because the step is only an enabler for our future use br of HDFS. However, it does help us think of HDFS as a filesystem; just like any new storage br device on any operating system, we need to format the device before we can use it. The br same is true for HDFS; initially there is a default location for the filesystem data but no br actual data for the equivalents of filesystem indexes.