hadoop - Clarity of terms used in HDFS? -


i have come across several terms while getting familiar hdfs. few of terms like: namespace, metadata, transaction logs, fsimage, editlogs.

sometimes appears these terms describe same thing, "having information", not clear on this.

in general metadata means data data metadata refer these terms or these terms have different purpose in context of hadoop hdfs?

namepace : within hadoop 'namespace' refers file names paths maintained name node.

metadata : includes name of file, size, permissions etc... metadata stored in file called fsimage.

fsimage : complete state of hdfs file system @ point of time.

any changes done filesystem not written fsimage there stored in separate file (on same location fsimage stored) called editlog.

editlogs: log lists each file system change made after recent fsimage.

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