This Jira targets to backport changes in
HDFS-14346 and HADOOP-16265 to allow better time precision of configuration#getTimeDuration. This is required by Standby read, where edit log tailing period needs to be set small.
HDFS-14346 is only partially backported in this Jira, as it has changes based on previous change from HDFS-9847. HDFS-9847 backport is not in the scope of this Jira. Therefore, this Jira only targets at backporting the minimum change required by Standby read.