https://community.cloudera.com/t5/Support-Questions/Can-not-start-HDFS-which-its-data-was-deleted-externally/m-p/212570#M174506 <P><EM>@<A href="https://community.hortonworks.com/users/15282/skestepe.html">Sedat Kestepe</A></EM></P><P><I><STRONG>Stop the Hdfs service</STRONG> if its running. </I></P><P><EM><STRONG>Start only the journal nodes</STRONG> (as they will need to be made aware of the formatting) </EM></P><P><EM> On the namenode (as user hdfs) </EM></P><PRE># su - hdfs </PRE><P><EM>Format the namenode </EM></P><PRE>$ hadoop namenode -format </PRE><P><EM>Initialize the Edits (for the journal nodes) </EM></P><PRE>$ hdfs namenode -initializeSharedEdits -force </PRE><P><EM>Format Zookeeper (to force zookeeper to reinitialise) </EM></P><PRE>$ hdfs zkfc -formatZK -force </PRE><P><EM>Using Ambari restart the namenode </EM></P><P><EM>If you are running HA name node then</EM></P><P><EM>On the second namenode Sync (force synch with first namenode) </EM></P><PRE>$ hdfs namenode -bootstrapStandby -force </PRE><P><EM>On every datanode clear the data directory which is already done in your case</EM></P><P><EM><STRONG>Restart the HDFS service </STRONG><BR /></EM></P><P><EM>Hope that helps</EM></P> Mon, 04 Dec 2017 22:15:49 GMT Shelton 2017-12-04T22:15:49Z