Timestamps on Cloud Object Stores
Timestamps of objects and directories in Cloud Object Stores do not follow the behavior of files and directories in HDFS:
The creation time of an object is the time when the object was created in the object store. This is at the end of the write process, not in the beginning.
If an object is overwritten, the modification time is updated.
Directories may or may not have valid timestamps. That is: if a "directory" is emulated in the client, it has no create time.
The
atimeaccess time feature is not supported by any of the object stores found in the Apache Hadoop codebase.
Without an atime timestamp, it is not possible to determine
if a directory has updated data by checking the timestamp.