The description of property dfs.namenode.stale.datanode.interval in hdfs-default.xml doesn't mention about the time unit, we should add that to avoid confusing users.
I have reviewed all properties in hdfs-default.xml, this is the only one property causes such confusion, user should be able to easily figure out the appropriate time unit for properties by either
- Specified by property name, e.g dfs.namenode.full.block.report.lease.length.ms
- Specified by property value with time unit suffix, e.g dfs.blockreport.initialDelay=0s
- Explained by description of the property, e.g dfs.namenode.safemode.extension=3000, description: Determines extension of safe mode in milliseconds ...
change to the property name and value will be an incompatible change, to minimize the impact, propose to simply add the time unit in the description (3rd approach). And this should be only one property needs the fix in hdfs-default.xml.