Configuring the global cache for multi-instance integration nodes
You can configure the global cache to withstand software or hardware failures so that it is available for as much time as possible. Configure a multi-instance integration node to host container servers by using an XML cache policy file.
Before you begin
For more information about the default global cache topology, see Data caching overview.
About this task
You can configure the global cache so that a multi-instance integration node hosts up to 4 container servers. If the active integration node instance fails, the standby integration node instance starts, and the container servers start up successfully within that integration node. As long as there is an active catalog server running elsewhere, the container servers rejoin the global cache. This mechanism does not allow a single-integration node cache to retain cached data on failover to a standby integration node instance
Consider the following example. Your global cache consists of two integration nodes that host catalog servers and container servers, and a multi-instance integration node. The active instance of the multi-instance integration node hosts up to 4 container servers. If the active instance of the multi-instance integration node fails, the cache will remain operational if at least one of the catalog servers is still available. Data is temporarily rebalanced across the remaining container servers in the integration node that host the catalog servers. When the standby instance of the multi-instance integration node starts, the container servers rejoin the global cache, and cached data is rebalanced automatically.
A multi-instance integration node cannot host a catalog server. Therefore, you cannot configure an integration server to host a catalog server if that integration server is defined with multiple listener hosts.
A sample XML cache policy file is provided as a starting point for your configuration. The policy_multi_instance.xml file configures three integration nodes in a high availability scenario. Two integration nodes each host a catalog server, and a multi-instance integration node hosts two container servers.
To configure a multi-instance integration node, a listenerHost element was introduced as an alternative to the listenerHost attribute of the integration node element. You can use the listenerHost element to specify a list of listener hosts. Alternatively, you can set the listenerHost property on the integration server to a comma-separated list of listener hosts.
The following steps describe how to configure the global cache for a multi-instance integration node.
Procedure
Results
mqsicacheadmin integrationNodeName -c showPlacement
You
can also use the mqsicacheadmin command to
show cache components in a multi-integration node cache. For example, the
listHosts command shows the host names, number of hosts, and
number of catalogs in the
cache:mqsicacheadmin integrationNodeName -c listHosts