This page provides information for self-managed customers configuring the data service. The data service configuration is specified in data-server-cluster
element in the appian-topology.xml
file, located in both the <APPIAN_HOME>/ae/data-server/conf/
and <APPIAN_HOME>/ae/conf/
directories:
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<topology>
...
<data-server-cluster>
<data-server host="machine1.example.com" port="5400" rts-count="2"/>
</data-server-cluster>
</topology>
For a high availability configuration, specify three instances of the data service on different machines:
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<topology>
...
<data-server-cluster>
<data-server host="machine1.example.com" port="5400" rts-count="2"/>
<data-server host="machine2.example.com" port="5400" rts-count="2"/>
<data-server host="machine3.example.com" port="5400" rts-count="2"/>
</data-server-cluster>
</topology>
You must specify the data-server-cluster
configuration in appian-topology.xml
. Copy the appian-topology.xml
file from <APPIAN_HOME>/conf/
into <APPIAN_HOME>/data-server/conf/
before starting the data service. Copies of the topology file in each location must always be in sync, irrespective of the configurations specified.
A data-server
node element must be present and must be structured similarly to the following:
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<data-server host="machine3.example.com" port="5400" rts-count="2"/>
If there is no data-server
node element specified, the following error is printed in watchdog.log
:
"ERROR com.appian.data.server.Watchdog - At least one data-server node must be specified"
Set the host
attribute in the data-server
element to the name of the machine hosting the data service. If the host
is not specified, the following error is printed in watchdog.log
:
"ERROR com.appian.data.server.Watchdog - data-server host must be specified"
You can define the port
attribute on both the data-server-cluster
and the data-server
elements. If the port
attribute is defined on both, the data-server
element takes precedence. If not supplied, the default port number is 5400
.
Caution: In order for the data service to function properly, make sure that you open all of the required ports. See Port Usage for more information.
The rts-count
attribute specifies the number of real-time stores in the data service. The real-time store component is responsible for processing queries to the data service, and each real-time store processes a single query at a time.
For self-managed customers, the rts-count
is set to 2 by default, but can be increased as needed to support increased query throughput. The maximum supported rts-count
varies based on the amount of memory available as shown below.
Available Memory | Supported RTS Count |
---|---|
Less than 32GB | 2 |
Between 32GB - 127GB | 4 |
Between 128GB - 384GB | 8 |
Greater than or equal to 384GB | 12 |
Topology changes can include:
To make these changes, you'll need to make configuration changes to the data-server-cluster
parameter and restart both the data service and the application server by following these steps:
<APPIAN_HOME>/data-server/bin/stop.sh
(.bat
on Windows)<APPIAN_HOME>/ae/data-server/node/election
directory from all the servers. This directory contains runtime data that needs to be deleted when certain topology changes are made.<APPIAN_HOME>/ae/data-server/data
directory to the new servers.<APPIAN_HOME>/data-server/bin/start.sh
(.bat
on Windows)<APPIAN_HOME>/tomcat/apache-tomcat/bin/stop-appserver.sh
(.bat
on Windows)<APPIAN_HOME>/tomcat/apache-tomcat/bin/start-appserver.sh
(.bat
on Windows)Configuring the Data Service