The various functions of Secondary NameNode are as follows. FsImage: It is used for storing a copy of FsImage file and EditLog. Checkpoint: In HDFS, Checkpoint is used by Secondary NameNode in order to detect any corrupted data present. NameNode crash: Secondary NameNode’s FsImage can be used for the purpose of recreating the NameNode in case of any NameNode crash. Update: It helps to keep the FsImage file updated on Secondary NameNode. It updates both FsImage file and EditLog automatically.