WebSphere eXtreme Scale Administration Guide > Administer the WebSphere eXtreme Scale environment > Start stand-alone WebSphere eXtreme Scale servers > Starting a stand-alone catalog service
Best practice: Clustering the catalog service
When you are using the catalog service, a minimum of two catalog servers are required to avoid a single point of failure. Depending on the number of nodes in the environment, you can create different configurations to ensure that at least two catalog servers are always running.
Number of catalog servers
The best practice to avoid a single point of failure for the catalog service domain is to start a minimum of three catalog servers on three different nodes.
If you are using only two nodes, configure two catalog servers on each of the two nodes for a total of four catalog server processes. Creating this configuration ensures that when only one of the nodes is started, the required two catalog servers are running. You must start at least two catalog servers at the same time. When catalog servers start, they look for other catalog servers in the configuration, and do not start successfully until at least one other catalog sever is found.
Example: Starting four catalog servers on two nodes in a stand-alone environment
The following script starts catalog servers cs0 and cs1 on the host1 node, and starts catalog servers cs2 and cs3 on the host2 node../startOgServer.sh cs0 -listenerPort 2809 -catalogServiceEndPoints cs0:host1:6601:6602,cs1:host1:6603:6604,cs2:host2:6601:6602,cs3:host2:6603:6604 -quorum true -jvmArgs -Xmx256m ./startOgServer.sh cs1 -listenerPort 2810 -catalogServiceEndPoints cs0:host1:6601:6602,cs1:host1:6603:6604,cs2:host2:6601:6602,cs3:host2:6603:6604 -quorum true -jvmArgs -Xmx256m ./startOgServer.sh cs2 -listenerPort 2809 -catalogServiceEndPoints cs0:host1:6601:6602,cs1:host1:6603:6604,cs2:host2:6601:6602,cs3:host2:6603:6604 -quorum true -jvmArgs -Xmx256m ./startOgServer.sh cs3 -listenerPort 2810 -catalogServiceEndPoints cs0:host1:6601:6602,cs1:host1:6603:6604,cs2:host2:6601:6602,cs3:host2:6603:6604 -quorum true -jvmArgs -Xmx256m
You must use the -listenerPort option because the catalog servers that are running on a node each require a unique port number.
Example: Starting multiple catalog servers in a WebSphere Application Server environment
Catalog servers start automatically in a WebSphere Application Server environment. You can define multiple catalog servers to start by creating a catalog service domain. After you specify multiple endpoints in the catalog service domain, restart the included application servers so that the catalog servers start in parallel.
- WebSphere Application Server Network Deployment: You can choose multiple existing application servers from the cell to be members of the catalog service domain.
- Base WebSphere Application Server: You can start the catalog service on multiple stand-alone nodes. By defining multiple profiles on the same installation image with the profile management tool, you can create a set of stand-alone nodes that each have unique ports assigned. In each application server, define the catalog service domain. You can specify any other application servers by adding remote servers to the configuration. After you create this configuration on all of the stand-alone servers, you can start the set of base application servers in parallel by running the startServer.bat|sh script or by using a Windows service to start the servers.
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Start a stand-alone catalog service