IBM® DB2® pureScale® (also known as DB2 application cluster transparency) feature introduced clustering technology to DB2 on distributed platforms, so you can deploy continuously available and scalable database clusters. The technology is based on the IBM DB2 for z/OS® architecture that businesses worldwide trust for their most critical systems.
IBM InfoSphere® Optim™ Configuration Manager for DB2 for LUW V3.1 (OCM) includes the following capabilities for IBM DB2 pureScale® feature:
- Tune the workload balancing properties of driver connection pooling on DB2 pureScale
Use OCM as a central console to review the following DB2 pureScale information
- DBCFG, DBMCFG parameters
- Product and license information
- DB2 pureScale group, members and cluster caching facility (also known as CF) information
- Architecture levels for the entire DB2 pureScale setup
Compare one DB2 pureScale environment (test) with another (production)
- Automate compare jobs to generate alerts when configurations deviate
- Review differences in configuration settings, database objects, and keep them in sync
- Support for rolling upgrades of DB2 pureScale
- Isolate application transactions to certain members of a DB2 pureScale group
- Throttle application connection to ensure mission critical applications are not starved of resources
Although there are many capabilities in OCM V3.1 for IBM DB2 pureScale® feature, this blog entry focuses on the isolate application transactions capability (#6 in the above list).
Isolate Application using Optim Configuration Manager:
Isolate applications on DB2 pureScale capability allows DBAs to isolate application workloads to certain members of a DB2 pureScale group. This capability is invaluable for enterprises when they want to:
- Isolate misbehaving applications and protect mission critical applications from cascading effects of the misbehaving applications
- Test new applications with production data in a limited capacity environment
I’ll use an example to describe this capability, the figure below shows the application “A” and “B” running on against a DB2 pureScale group. DB2 pureScale member “2” has been identified as the member on which isolated applications will execute (penalty box).
A user can identify misbehaving applications (applications that may have an unusually high CPU utilization) via IBM InfoSphere Optim Performance Manager for DB2 for LUW (OPM). OPM can also identify impacted applications. In the example, application “B” is the misbehaving application and as a result the resources available to application “A” are impacted. The mission critical application “A” therefore has poor response times and the effect cascades to any other applications running on the DB2 pureScale group.
OCM can be invoked from the OPM dashboard.
You can define and use client rules in OCM to control applications connecting to DB2 for LUW servers. Additionally, rules can be used to control drivers, data sources, and transactions of user applications and the connections to DB2 for LUW servers. You can create client rules for managed clients only. Managed clients are those clients on which IBM InfoSphere Optim Data Tools Runtime Client is installed. Before you create a rule, you first need to create a rule set, which is a named group of rules.
A rule with “Isolate application transactions” type can be defined which isolates a resource-consuming application on DB2 pureScale to a restricted environment so that other applications can obtain the resources they need to perform optimally. This rule moves an application, a group of applications, or a workload within an application to a pre-configured location alias (penalty box) of a specific member in a DB2 pureScale.
Steps to isolate an application to specific DB2 pureScale member(s) in Optim Configuration Manager:
The following steps are not comprehensive; I’ve attempted to highlight the steps involved in isolating an application.
Step 1: Setup up a location alias for members in a DB2 pureScale group
For a DB2 pureScale group, you can define or update DB2 pureScale aliases using a DB2 call to the SYSPROC.WLM_CREATE_MEMBER_SUBSET stored procedure.
For example to create a location alias called MY_PBOX for DB2 pureScale member ID 2:
A location alias represents one, a subset, or all members of a data sharing group.
The following screen shot shows location aliases ALIAS1 for DB2 pureScale member ID 1, ALIAS01 for DB2 pureScale member ID 0 and 1, and PBOX for DB2 pureScale member ID 2.
Step 2: Define a rule to isolate an application
To create a rule for a managed client, choose Open > Managed Clients, select the application client and click on “Add Rule…”.
The “Rule Set Manager” tab is opened and the Rule Set name, which was automatically created when the connection to the DB2 pureScale server was defined, is automatically filled in. Specify any Name for the rule (“PBOX” in the following screen shot) and Isolate Application Transactions as the Action to be performed by this rule.
The conditions for identifying the client application are automatically filled in as shown in the screen shot below. Edit the conditions if necessary.
In the Action tab specify the Alias Name to isolate the application to certain member(s) of the DB2 pureScale group.
Save the Rule Set.
Step 3: Activate the rule set
Activate the rule set. Once the rule set has been activated, OCM directs new connections to the DB2 pureScale members identified by the location alias “PBOX”.
The following screen shot shows the activated Rule Set.