FAQ for Cluster Setup

About 3 min

1. Cluster StartUp and Stop

Make sure that the data/confignode directory is cleared when start ConfigNode for the first time.
Make sure that the <IP+Port> used by ConfigNode is not occupied, and the <IP+Port> is also not conflicted with other ConfigNodes.
Make sure that the cn_target_confignode_list is configured correctly, which points to the alive ConfigNode. And if the ConfigNode is started for the first time, make sure that cn_target_confignode_list points to itself.
Make sure that the configuration(consensus protocol and replica number) of the started ConfigNode is accord with the cn_target_confignode_list ConfigNode.

Examine whether the cn_target_confignode_list points to the correct address. If cn_target_confignode_list points to itself, a new ConfigNode cluster is started.

Make sure that the data/datanode directory is cleared when start DataNode for the first time. If the start result is “Reject DataNode restart.”, maybe the data/datanode directory is not cleared.
Make sure that the <IP+Port> used by DataNode is not occupied, and the <IP+Port> is also not conflicted with other DataNodes.
Make sure that the dn_target_confignode_list points to the alive ConfigNode.

Examine whether the parameter of remove-datanode.sh is correct, only rpcIp:rpcPort and dataNodeId are correct parameter.
Only when the number of available DataNodes in the cluster is greater than max(schema_replication_factor, data_replication_factor), removing operation can be executed.
Removing DataNode will migrate the data from the removing DataNode to other alive DataNodes. Data migration is based on Region, if some regions are migrated failed, the removing DataNode will always in the status of Removing.
If the DataNode is in the status of Removing, the regions in the removing DataNode will also in the status of Removing or Unknown, which are unavailable status. Besides, the removing DataNode will not receive new write requests from client.
And users can use the command set system status to running to make the status of DataNode from Removing to Running;
If users want to make the Regions from Removing to available status, command migrate region from datanodeId1 to datanodeId2 can take effect, this command can migrate the regions to other alive DataNodes.
Besides, IoTDB will publish remove-datanode.sh -f command in the next version, which can remove DataNodes forced (The failed migrated regions will be discarded).

The down DataNode can be removed only when the replica factor of schema and data is greater than 1.
Besides, IoTDB will publish remove-datanode.sh -f function in the next version.

The file structure between 0.13 and 1.0 is different, we can't copy the data directory from 0.13 to 1.0 to use directly.
If you want to load the data from 0.13 to 1.0, you can use the LOAD function.
The default RPC address of 0.13 is 0.0.0.0, but the default RPC address of 1.0 is 127.0.0.1.

Can't. The running result will be "Reject ConfigNode restart. Because there are no corresponding ConfigNode(whose nodeId=xx) in the cluster".

Can't. The running result will be "Reject DataNode restart. Because there are no corresponding DataNode(whose nodeId=xx) in the cluster. Possible solutions are as follows:...".

We can use remove-datanode.sh to fix it. Remove-datanode will migrate the data in the removing DataNode to other alive DataNodes.
IoTDB will publish Node-Fix tools in the next version.

Adjust the MAX_HEAP_SIZE、MAX_DIRECT_MEMORY_SIZE options in conf/confignode-env.sh and conf/datanode-env.sh.