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Limiting Concurrent vBucket Moves

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    Couchbase Server places a limit on the number of concurrent vBucket moves that can occur during rebalance, applying the limit to every node in the cluster. This limit can be inspected and reset by means of the REST API.

    HTTP methods and URI

    GET /settings/rebalance
    
    POST /settings/rebalance

    Description

    These respectively retrieve and establish the setting whereby the number of concurrent vBucket moves that any node can handle during rebalance is limited. See Limiting vBucket Moves, for detailed information.

    Curl Syntax

    curl -X GET -u <administrator>:<password>
       http://<host>:<port>/settings/rebalance
    
    curl -X POST -u <administrator>:<password>
       http://<host>:<port>/settings/rebalance
       -d rebalanceMovesPerNode=<positive-integer>

    The positive-integer used as the value for the rebalanceMovesPerNode parameter must be between 1 and 64 inclusive, with 4 being the default.

    Responses

    If successful, 200 OK is given, and an object containing group-related information is returned.

    A malformed URI gives 400 Object Not Found. Failure to authenticate gives 401 Unauthorized.

    If an inappropriate value is specified, the following error-notification is returned: {"errors":{"rebalanceMovesPerNode":"The value must be in range from 1 to 64"}}.

    Examples

    The following example retrieves the current setting for vBucket move limitation:

    curl -X GET -u Administrator:password \
    http://localhost:8091/settings/rebalance

    If successful, the call returns an object such as the following:

    {"rebalanceMovesPerNode":4}

    This indicates that the current setting is 4, which is the default.

    The following example establishes a new value for the setting:

    curl -X POST -u Administrator:password \
    http://localhost:8091/settings/rebalance \
    -d rebalanceMovesPerNode=12

    If successful, the call returns an object such as the following:

    {"rebalanceMovesPerNode":12}

    This confirms that the value has been successfully reset to 12.

    See Also

    A complete conceptual overview of rebalance is provided in Rebalance. Information on inspecting and modifying Couchbase-Server settings is provided in Manage Settings. Various examples of performing rebalance and other node-management operations can be found in Manage Nodes and Clusters.