In CDH4 and later, which file contains a serialized form of all the directory and files inodes in the
filesystem, giving the NameNode a persistent checkpoint of the filesystem metadata?

A.
fstime

B.
VERSION

C.
Fsimage_N (Where N reflects all transactions up to transaction ID N)

D.
Edits_N-M (Where N-M specifies transactions between transactions ID N and transaction ID N)

Explanation:
http://mikepluta.com/tag/namenode/