As like in ASM, when ever a disk is added a rebalance operation takes place between the disks, similarly when the replication factor is changed at keyspace level in the cassandra, the rebalance operation should take place, I have changed the replication factor for Keyspace and you should start the repair of each node so data is again redistributed and key ranges will be adjusted..
root@wash-i-16ca26c8-prod ~/.ccm/repository/4.5.2/demos/portfolio_manager/bin $ ccm node1 cqlsh
Connected to geek_cluster at 127.0.0.1:9160.
[cqlsh 4.1.1 | Cassandra 2.0.10.71 | DSE 4.5.2 | CQL spec 3.1.1 | Thrift protocol 19.39.0]
Use HELP for help.
cqlsh> ALTER KEYSPACE "Excalibur" WITH REPLICATION ={ 'class' : 'SimpleStrategy', 'replication_factor' : 3 };
root@wash-i-16ca26c8-prod ~/.ccm/repository/4.5.2/demos/portfolio_manager/bin $ ccm node1 nodetool repair
[2016-07-11 01:47:05,302] Nothing to repair for keyspace 'system'
[2016-07-11 01:47:05,310] Starting repair command #1, repairing 3 ranges for keyspace PortfolioDemo
[2016-07-11 01:47:12,591] Repair session 5edc4330-4709-11e6-a73e-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:47:12,591] Repair session 60ae9230-4709-11e6-a73e-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:47:12,717] Repair session 621ec400-4709-11e6-a73e-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:47:12,717] Repair command #1 finished
[2016-07-11 01:47:12,725] Starting repair command #2, repairing 4 ranges for keyspace dse_system
[2016-07-11 01:47:14,173] Repair session 6346f050-4709-11e6-a73e-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:47:14,174] Repair session 638076e0-4709-11e6-a73e-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:47:14,175] Repair session 63b828b0-4709-11e6-a73e-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:47:14,175] Repair session 63ed4270-4709-11e6-a73e-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:47:14,175] Repair command #2 finished
[2016-07-11 01:47:14,182] Starting repair command #3, repairing 2 ranges for keyspace system_traces
[2016-07-11 01:47:14,529] Repair session 64254260-4709-11e6-a73e-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:47:14,534] Repair session 64401d60-4709-11e6-a73e-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:47:14,534] Repair command #3 finished
root@wash-i-16ca26c8-prod ~/.ccm/repository/4.5.2/demos/portfolio_manager/bin $ ccm node2 nodetool repair
[2016-07-11 01:47:58,676] Nothing to repair for keyspace 'system'
[2016-07-11 01:47:58,682] Starting repair command #1, repairing 3 ranges for keyspace PortfolioDemo
[2016-07-11 01:48:03,446] Repair session 7eac2ef0-4709-11e6-b499-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:03,446] Repair session 800be600-4709-11e6-b499-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:48:03,453] Repair session 81086e70-4709-11e6-b499-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:48:03,453] Repair command #1 finished
[2016-07-11 01:48:03,463] Starting repair command #2, repairing 4 ranges for keyspace dse_system
[2016-07-11 01:48:04,869] Repair session 8184f170-4709-11e6-b499-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:48:04,869] Repair session 81bc5520-4709-11e6-b499-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:04,870] Repair session 81f1e410-4709-11e6-b499-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:48:04,871] Repair session 82230630-4709-11e6-b499-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:48:04,871] Repair command #2 finished
[2016-07-11 01:48:04,878] Starting repair command #3, repairing 2 ranges for keyspace system_traces
[2016-07-11 01:48:05,287] Repair session 825cdae0-4709-11e6-b499-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:05,292] Repair session 82812bc0-4709-11e6-b499-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:48:05,292] Repair command #3 finished
root@wash-i-16ca26c8-prod ~/.ccm/repository/4.5.2/demos/portfolio_manager/bin $ ccm node3 nodetool repair
[2016-07-11 01:48:12,500] Nothing to repair for keyspace 'system'
[2016-07-11 01:48:12,506] Starting repair command #1, repairing 3 ranges for keyspace PortfolioDemo
[2016-07-11 01:48:16,205] Repair session 86e967e0-4709-11e6-bd37-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:48:16,205] Repair session 87c98eb0-4709-11e6-bd37-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:16,211] Repair session 88bc5320-4709-11e6-bd37-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:48:16,211] Repair command #1 finished
[2016-07-11 01:48:16,219] Starting repair command #2, repairing 4 ranges for keyspace dse_system
[2016-07-11 01:48:17,591] Repair session 891f5ab0-4709-11e6-bd37-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:48:17,591] Repair session 89511910-4709-11e6-bd37-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:17,592] Repair session 89891900-4709-11e6-bd37-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:48:17,593] Repair session 89bd9680-4709-11e6-bd37-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:48:17,593] Repair command #2 finished
[2016-07-11 01:48:17,600] Starting repair command #3, repairing 2 ranges for keyspace system_traces
[2016-07-11 01:48:17,885] Repair session 89f21400-4709-11e6-bd37-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:48:17,889] Repair session 8a05c310-4709-11e6-bd37-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:48:17,889] Repair command #3 finished
root@wash-i-16ca26c8-prod ~/.ccm/repository/4.5.2/demos/portfolio_manager/bin $ ccm node4 nodetool repair
[2016-07-11 01:48:25,045] Nothing to repair for keyspace 'system'
[2016-07-11 01:48:25,051] Starting repair command #1, repairing 3 ranges for keyspace PortfolioDemo
[2016-07-11 01:48:27,804] Repair session 8e63c600-4709-11e6-8071-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:48:27,804] Repair session 8ee81130-4709-11e6-8071-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:27,809] Repair session 8f92d020-4709-11e6-8071-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:48:27,809] Repair command #1 finished
[2016-07-11 01:48:27,817] Starting repair command #2, repairing 4 ranges for keyspace dse_system
[2016-07-11 01:48:29,062] Repair session 90091190-4709-11e6-8071-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:48:29,062] Repair session 90397060-4709-11e6-8071-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:29,063] Repair session 906896b0-4709-11e6-8071-e7c99fc0dbe2 for range (3074457345618258602,-9223372036854775808] finished
[2016-07-11 01:48:29,068] Repair session 90957310-4709-11e6-8071-e7c99fc0dbe2 for range (1415355439304195653,3074457345618258602] finished
[2016-07-11 01:48:29,069] Repair command #2 finished
[2016-07-11 01:48:29,080] Starting repair command #3, repairing 2 ranges for keyspace system_traces
[2016-07-11 01:48:29,367] Repair session 90c9c980-4709-11e6-8071-e7c99fc0dbe2 for range (-3074457345618258603,1415355439304195653] finished
[2016-07-11 01:48:29,372] Repair session 90e05ec0-4709-11e6-8071-e7c99fc0dbe2 for range (-9223372036854775808,-3074457345618258603] finished
[2016-07-11 01:48:29,372] Repair command #3 finished
-Thanks
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