clickhouse-copier

The description of the utility and its parameters, as well as examples of the config files that you need to create for the copier are in the doc https://clickhouse.tech/docs/en/operations/utilities/clickhouse-copier/

The steps to run a task:

Create a config file for clickhouse-copier (zookeeper.xml)

https://clickhouse.tech/docs/en/operations/utilities/clickhouse-copier/#format-of-zookeeper-xml
Create a config file for the task (task1.xml)

https://clickhouse.tech/docs/en/operations/utilities/clickhouse-copier/#configuration-of-copying-tasks
Create the task in ZooKeeper and start an instance of clickhouse-copierclickhouse-copier --daemon --base-dir=/opt/clickhouse-copier --config /opt/clickhouse-copier/zookeeper.xml --task-path /clickhouse/copier/task1 --task-file /opt/clickhouse-copier/task1.xml

If the node in ZooKeeper already exists and you want to change it, you need to add the task-upload-force parameter:

clickhouse-copier --daemon --base-dir=/opt/clickhouse-copier --config /opt/clickhouse-copier/zookeeper.xml --task-path /clickhouse/copier/task1 --task-file /opt/clickhouse-copier/task1.xml --task-upload-force 1

If you want to run another instance of clickhouse-copier for the same task, you need to copy the config file (zookeeper.xml) to another server, and run this command:

clickhouse-copier --daemon --base-dir=/opt/clickhouse-copier --config /opt/clickhouse-copier/zookeeper.xml --task-path /clickhouse/copier/task1

The number of simultaneously running instances is controlled be the max_workers parameter in your task configuration file. If you run more workers superfluous workers will sleep and log messages like this:

<Debug> ClusterCopier: Too many workers (1, maximum 1). Postpone processing

clickhouse-copier

See also

clickhouse-copier 20.3 and earlier

clickhouse-copier 20.4 - 21.6