Configuring Informix® Warehouse Accelerator for hardware clusters

You must configure Informix® Warehouse Accelerator before you can enable query acceleration and set up the connection between the accelerator server and the database server. In a cluster system, one accelerator server coordinator node uses the first cluster node, and then each cluster node that you add to the cluster becomes an accelerator server worker node.

Before you begin

Prerequisite: Test that user root or user informix can run the Secure Shell (SSH) network protocol without a password between all cluster nodes.

About this task

Configure the accelerator server by identifying the network interface, creating a storage directory, editing the parameters in the dwainst.conf configuration file, and creating a cluster.conf file.

Procedure

On one of the cluster nodes where the accelerator server is installed, log on as user root.
Determine the correct network interface value to use for the connection from the Informix® database server to the accelerator server:
1. Run the Linux™ ifconfig system command to retrieve the information about the network devices on your system.
2. Review the output with your system administrator and network administrator and select the appropriate value to use.
  Examples of network interface values are eth0 or peth0.
On the shared cluster file system, create a directory to use as the accelerator server storage directory. The storage directory must be accessible with the same path on all cluster nodes. Create this directory with enough space to store the accelerator server catalog, data marts, logs, traces, and so on.
For example:
```
$ mkdir $IWA_INSTALL_DIR/dwa/demo
```
Because the amount of data in the accelerator server storage directory might increase significantly, do not create the accelerator server storage directory in the accelerator server installation directory.
Open the $IWA_INSTALL_DIR/dwa/etc/dwainst.conf configuration file. Review and edit the values in the dwainst.conf configuration file:
1. For the DRDA_INTERFACE parameter, specify the network interface value that you identified in step 2.
2. For the DWADIR parameter, specify the file path for the storage directory that you created in step 3.
  On all cluster nodes, the DWADIR parameter must be the same file path.
3. For the CLUSTER_INTERFACE parameter, specify the network device name for the connection between the cluster nodes.
  For example, eth0.
4. If only one coordinator node or one worker node will run on each cluster node, add the following additional parameters and values:
```
CORES_FOR_SCAN_THREADS_PERCENTAGE=100
CORES_FOR_LOAD_THREADS_PERCENTAGE=100
CORES_FOR_REORG_THREADS_PERCENTAGE=25
```
In the $IWA_INSTALL_DIR/dwa/etc directory, create a file named cluster.conf to store the host names or IP addresses of the cluster nodes. In the cluster.conf file, enter one cluster node per line. For example:
```
node0001
node0002
node0003
node0004
```
The order that you list the hosts names (or their IP addresses) of the cluster nodes is the order that the cluster nodes are started or stopped with the ondwa start and ondwa stop commands.
Use the ondwa commands to set up and start the accelerator server. You can run the ondwa commands from any node in the cluster. The ondwa commands apply to all the nodes listed in the cluster.conf file.
1. Run the ondwa setup command to create the files and subdirectories that are required to run the accelerator server.
  Example output:
```
Checking for DWA_CM_node0 on node0001: stopped
Checking for DWA_CM_node1 on node0002: stopped
Checking for DWA_CM_node2 on node0003: stopped
Checking for DWA_CM_node3 on node0004: stopped
```
2. Run the ondwa start command to start all of the cluster nodes.
  Example output:
```
Starting DWA_CM_node0 on node0001: started
Starting DWA_CM_node1 on node0002: started
Starting DWA_CM_node2 on node0003: started
Starting DWA_CM_node3 on node0004: started
```