--- title: "gpdemo" source: https://cloudberry.apache.org/docs/sys-utilities/gpdemo --- # gpdemo You can use the built-in `gpdemo` script to quickly deploy a cluster with a specified number of segments only with a single command. `gpdemo` is installed with other system utilities (such as `gpinitsystem`, `gpstart`, and `gpstop`) in the `GPHOME/bin` directory. :::warning It is not recommended to use `gpdemo` for production environments, except when deploying a single node cluster. ::: ## How to use You can run `gpdemo` once the RPM package is installed on the target server and `greenplum_path.sh` is correctly loaded. ### Deploy with default settings To quickly deploy a cluster without special requirements for the data directory location, initial port number, or segment count, you can run `gpdemo` without any parameter: ```bash gpdemo ``` After running this command, the script creates a cluster in the current path. The default configuration of the cluster is as follows: - Segment count: 3 - Data directory: `./datadirs` - The initial port number of coordinator: `7000` :::info Once a cluster is deployed, the script generates the `gpdemo-env.sh` file in the current directory containing the basic information of the cluster. Before using `gpdemo` to operate on the cluster, run `source gpdemo-env.sh` to load this information. You need to run this command for each new shell session. To load the cluster information automatically, you can add this command to `~/.bashrc` or `~/.zshrc`. ::: ### Deploy with customized settings If you need to customize the number of segments, data directory location, and the initial port number of the cluster, refer to the following instructions. #### Specify segment count For the default deployment, the number of segments in a cluster is 3. To specify the number of segments in a cluster, you can add the `NUM_PRIMARY_MIRROR_PAIRS` parameter to the `gpdemo` command. For example, to specify the number of segments as 3, you can run: ```bash NUM_PRIMARY_MIRROR_PAIRS=3 gpdemo ``` :::info - Each segment node consists of a primary node and a mirror node. So every time the parameter value increases by `1`, 2 more nodes will be created. To better capture data distribution issues, it is recommended to set the value to an odd number. - When the parameter value is set to 0, a single-computing-node cluster is deployed. See [Deploy Apache Cloudberry with a Single Computing Node](../deployment/single-node.md) for details. ::: #### Specify the data directory of a node Each node's data in a cluster is stored in the `./datadirs` subdirectory of the current directory. To set the cluster's data directory location, use one of the following methods: - Switch to the target directory using `cd` and run `gpdemo`. - In the `gpdemo` command, specify the `DATADIRS` parameter to set the data directory. For example: ```bash DATADIRS=/target/directory/ gpdemo ``` :::info After a cluster is deployed, if you want to manually adjust the location of the data directory (by modifying the `pg_hha.conf`configuration file), you might need to know the default directories of the coordinator node and segment nodes. - Regular multi-node mode (which means `NUM_PRIMARY_MIRROR_PAIRS` > 0) - Coordinator: `./datadirs/qddir` - Coordinator Standby: `./datadirs/standby` - Segments - Primary: `./datadirs/dbfast`, where `` is the segment number. - Mirror: `./datadirs/dbfast_mirror`, where ``is the segment number. - Single-node mode (which means `NUM_PRIMARY_MIRROR_PAIRS` = 0) - Coordinator: `./datadirs/singlenodedir` - Coordinator Standby: `./datadirs/standby` ::: #### Specify the initial port number of the coordinator node By default, the port number of the Coordinator node is `7000`. Starting from this number, all other nodes in the cluster are assigned consecutive port numbers. To specify the initial port number of a cluster's coordinator node, you can add the `PORT_BASE` parameter to the `gpdemo` command. For example: ```bash PORT_BASE=7000 gpdemo ``` #### Specify additional initialization parameter for each node in the cluster `BLDWRAP_POSTGRES_CONF_ADDONS` specifies the additional initialization parameter for each node in a cluster. The default value `fsync=off` is for better concurrency performance. **In a production environment, use `export BLDWRAP_POSTGRES_CONF_ADDONS ="fsync=on"` to enable fsync. Otherwise, the ACID characteristics of the database will be affected. In the single-node mode, fsync is automatically enabled.** ## Command-line options `gpdemo` provides the following command-line options. You can also check them using `gpdemo -H`. | Option | Description | | ------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `-K` | Skips the data consistency check when deploying a cluster. This option is not recommended. | | `-c` | Checks the port occupancy and confirms whether a test cluster can be deployed.

Before running `gpdemo -c`, you need to run `source gpdemo-env.sh` to load the basic information of a cluster. The `sh` file is located in the directory where the cluster is created. | | `-d` | Deletes the test cluster.

Before running `gpdemo -c`, you need to run `source gpdemo-env.sh` to load the basic information of a cluster. The `sh` file is located in the directory where the cluster is created. | | `-p` | Views cluster status, version and other information of the coordinator and segment nodes.

Before running `gpdemo -c`, you need to run `source gpdemo-env.sh` to load the basic information of a cluster. The `sh` file is located in the directory where the cluster is created. | | `-H ` or `-H` | `gpdemo -h` outputs a brief help description.`gpdemo -H` outputs a more detailed help description, including additional configurations such as environment variables. | | `-v` | Checks the current `gpdemo` version. |