repair

Repairs one or more tables.

Synopsis 

nodetool <options> repair
 ( -dc <dc_name> | --in-dc <dc_name> )
 ( -et <end_token> | --end-token <end_token> )
 ( -local | --in-local-dc )
 ( -par | --parallel )
 ( -pr | --partitioner-range )
 ( -st <start_token> --start-token <start_token> )
-- <keyspace> ( <table> ... )

• options are:
  • ( -h | --host ) <host name> | <ip address>
  • ( -p | --port ) <port number>
  • ( -pw | --password ) <password >
  • ( -u | --username ) <user name>
• -dc, or --in-dc, followed by dc_name, or means restrict repair to nodes in the named data center, which must be the local data center.
• -et, or --end-token, followed by the UUID of a token means stop repairing a range of nodes after repairing this token.
• -local, or --in-local-dc, means repair nodes in the same data center only.
• -par, or --parallel, means carry out a parallel repair.
• pr, or --partitioner-range, means repair only the first range returned by the partitioner.
• -st, or --start-token, followed by the UUID of a token means start repairing a range of nodes at this token.
• -- Separates an option and argument that could be mistaken for a option.
• keyspace is the keyspace name.
• table is one or more table names, separated by a space.

Description 

This command operates on multiple nodes in a cluster, and includes an option to restrict repair to a set of nodes. This command begins an anti-entropy node repair operation. If the -pr option is specified, only the first range returned by the partitioner for a node is repaired. This allows you to repair each node in the cluster in succession without duplicating work. If the -pr option is not specified, Cassandra repairs all replica ranges that fall within the responsibility of the node.

By default, the repair command takes a snapshot of each replica immediately and then sequentially repairs each replica from the snapshots. For example, if you have RF=3 and A, B and C represents three replicas, this command takes a snapshot of each replica immediately and then sequentially repairs each replica from the snapshots (A<->B, A<->C, B<->C) instead of repairing A, B, and C all at once. This allows the dynamic snitch to maintain performance for your application via the other replicas, because at least one replica in the snapshot is not undergoing repair.

Unlike sequential repair (described above), parallel repair constructs the Merkle tables for all nodes at the same time. Therefore, no snapshots are required (or generated). Use a parallel repair to complete the repair quickly or when you have operational downtime that allows the resources to be completely consumed during the repair.

To restrict the repair to the local data center, use the -dc option followed by the name of the data center. Issue the command from a node in the data center you want to repair. Issuing the command from a data center other than the named one returns an error. Do not use -pr with this option to repair only a local data center.

$ nodetool repair -dc DC1
[2014-07-24 21:59:55,326] Nothing to repair for keyspace 'system'
[2014-07-24 21:59:55,617] Starting repair command #2, repairing 490 ranges 
  for keyspace system_traces (seq=true, full=true)
[2014-07-24 22:23:14,299] Repair session 323b9490-137e-11e4-88e3-c972e09793ca 
  for range (820981369067266915,822627736366088177] finished
[2014-07-24 22:23:14,320] Repair session 38496a61-137e-11e4-88e3-c972e09793ca 
  for range (2506042417712465541,2515941262699962473] finished
. . .

An inspection of the system.log shows repair taking place only on IP addresses in DC1.

. . .
INFO  [AntiEntropyStage:1] 2014-07-24 22:23:10,708 RepairSession.java:171 
  - [repair #16499ef0-1381-11e4-88e3-c972e09793ca] Received merkle tree 
  for sessions from /192.168.2.101
INFO  [RepairJobTask:1] 2014-07-24 22:23:10,740 RepairJob.java:145 
  - [repair #16499ef0-1381-11e4-88e3-c972e09793ca] requesting merkle trees 
  for events (to [/192.168.2.103, /192.168.2.101])
. . .

For more information about the repair operation, see "Repairing nodes."