Interfaces for retrieving status information for Db2 pureScale instances

To see the overall status of various components in your Db2 pureScale instance, you can choose from a number of administrative views, table functions, and CLP commands. In addition, there are commands that you can use from the system command prompt or shell, which are useful when any of the server components are not running.
You can view state and alert information about your Db2 pureScale instance in the following ways:

Table functions and administrative views

Table functions provide a flexible interface for retrieving information about your system. Most table functions accept parameters to narrow the scope of the information returned. For example, you might be interested in viewing information about a specific host.

Administrative views provide quick and easy access to system information. Unlike table functions, you cannot pass parameters to an administrative view to narrow the scope of a query. Generally, information for all objects relevant to the view (for example, hosts, cluster caching facilities (also known as CFs) or members) in the system are returned. You can always filter the output of administrative views using SQL, however.

The following table functions and their corresponding administrative views return information about the overall status of a Db2 pureScale instance:
Table 1. Table functions and administrative views that display status information for components in a Db2 pureScale instance
Interface Description
DB2_GET_CLUSTER_HOST_STATE table function
DB2_CLUSTER_HOST_STATE administrative view
 These interfaces provide basic information about the hosts that comprise a Db2 pureScale instance. They return a list of hosts and associated state information.
DB2_GET_INSTANCE_INFO table function
DB2_MEMBER administrative view
DB2_CF administrative view
 These interfaces provide more detailed information about a Db2 pureScale instance. They return information about the role in the instance each host plays (cluster caching facility or member), whether each cluster caching facility or member is running on its home host, and connection information for each host. 
DB2_INSTANCE_ALERTS administrative view
 This interface provides information about alerts in a Db2 pureScale instance.
Note: Each of the preceding interfaces can be used in both Db2 pureScale instances and other Db2 instances. The results they return for each might be different. For example, the DB2_MEMBER administrative view can be used for both types of instances; however, in an instance outside of a Db2 pureScale environment, no state or alert information is included in the information returned. You must remember to interpret the results returned from the functions and views in the context of the type of instance that is being queried. Consult the reference topics for each of the specific table functions or administrative views for details.

CLP commands

The following commands can be used from the command-line processor (CLP):
Table 2. CLP commands that display status information for components in a Db2 pureScale instance
CLP command Description
LIST INSTANCE This command returns information about the state of members, hosts, and cluster caching facilities.
LIST INSTANCE SHOW DETAIL This command is an extension of the LIST INSTANCE command that returns added information, including partition number and connection information for members, hosts, and cluster caching facilities.

System prompt (shell) commands

The following commands can be used from the system or shell prompt:
Table 3. System prompt (shell) commands that display information for components in a Db2 pureScale instance
Command Description
db2instance -list This command returns status information about members, hosts, and cluster caching facilities in a Db2 pureScale instance. It can be used even if there is no current database connection, or if the instance is stopped. In the latter case, the db2instance -list command works with the cluster manager to report the information about the hosts in the Db2 pureScale instance. There are several options available that restrict the output to members only, or cluster caching facilities only.
db2cluster options This command can be used to view information about Db2 pureScale instances. There are several additional options to choose from for this command; when you specify the -list option, you must also specify additional options to specify what to include in the command output.