Cell TTL is something that is defined at insertion time. So for an already existing data, you can perform a put of the same cell, which then will have the exact cell value on a new Hfile with the new TTL for the cell. ... View more

As HDFS-3743 still remains unresolved. I don't see any feature in the CM to copy the edits from the live journal node to the newly added journal node. Deploying the role using CM will add the role but the Active Namenode will report that its "out of sync" with this new journal node. So before starting the new journal node, copy the edits directory from one of the existing JournalNodes to the new one.   1 - Stop the New JN. 2 - Copy all the contents under /current of Journalnode folder from a working Journalnode to the new Journal node. 3 - Add the right permission to the newly copied folders with chown and chmod. 4 - Delete the edit_inprogress file (inside the new Journal node) such that the new Journalnode will start synchronising this file with the older Journal nodes.   ... View more

Ensure that at OS level the Namenode disk is mounted with read/write options ... View more

There is no direct method or property to disable tombstone marker. Major compacting the mob CF is the only way to go. There is a mob cleaner running on master that removes unreferenced mob files: The period of the cleaner chore can be configured by setting hbase.master.mob.cleaner.period to a positive integer number of seconds. It defaults to running daily. You should not need to tune it unless you have a very aggressive TTL or a very high rate of MOB updates with a correspondingly high rate of non-MOB compactions. So you can check and set the above parameter value and can manually trigger mob compaction by specifying the cf that includes mob data in hbase shell.   NOTE : MOBs are mostly for writing large cells that will rarely be updated or deleted but could have TTL configured for the cell or CF. ... View more