DB2 Version 9.7 for Linux, UNIX, and Windows

IBM Tivoli System Automation for Multiplatforms (Linux and AIX®)

IBM® Tivoli® System Automation for Multiplatforms (Tivoli SA MP) is cluster managing software that facilitates automatic switching of users, applications, and data from one database system to another in a cluster. Tivoli SA MP automates control of IT resources such as processes, file systems, and IP addresses.

Tivoli SA MP provides a framework to automatically manage the availability of what are known as resources. Examples of resources are:

Any piece of software for which start, monitor, and stop scripts can be written to control
Any network interface card (NIC) to which Tivoli SA MP has been granted access. That is, Tivoli SA MP will manage the availability of any IP address that a user wants to use by floating that IP address amongst NICs that it has been granted access to.

For example, both a DB2® instance and the High Availability Disaster Recovery feature, have start, stop, and monitor commands. Therefore, Tivoli SA MP scripts can be written to automatically manage these resources. Resources that are closely related (for example, ones that collectively run on the same node at the same time) are called a resource group.

DB2 resources

In a single-partition DB2 environment, a single DB2 instance is running on a server. This DB2 instance has local access to data (its own executable image as well as databases owned by the instance). If this DB2 instance is made accessible to remote clients, an unused IP address must be assigned to this DB2 instance.

The DB2 instance, the local data, and the IP address are all considered resources, which must be automated by Tivoli SA MP. Since these resources are closely related (for example, they collectively run on the same node at the same time), they are called a resource group.

The entire resource group is collocated on one node in the cluster. In the case of a failover, the entire resource group is started on another node.

The following dependencies exist between the resources in the group:

The DB2 instance must be started after the local disk
The DB2 instance must be stopped before the local disk
The HA IP address must be collocated with the instance

Disk storage

The DB2 database can utilize these resources for local data storage:

Raw disk (for example, /dev/sda1)
Logical volume managed by Logical Volume Manager (LVM)
File system (for example, ext3, jfs)

DB2 data can be stored either entirely on one or more raw disks, entirely on logical volumes, entirely on file systems, or on a mixture of all three. Any executables need to reside on a file system of some sort.

DB2 database requirements for the HA IP address

The DB2 database has no special requirements for the IP address. It is not necessary to define a highly available IP address in order for the instance to be considered highly available. However, it is important to remember that the IP address that is protected (if any) is the client's access point to the data, and as such, this address must be well known by all clients. In practice, it is recommended that this IP address be the one that is used by the clients in their CATALOG TCPIP NODE commands.

Tivoli SA MP resource groups

IBM Tivoli System Automation for Multiplatforms is a product that provides high availability by automating resources such as processes, applications, IP addresses, and others in Linux-based clusters. To automate an IT resource (such as an IP address), the resource must be defined to Tivoli SA MP. Furthermore, these resources must all be contained in at least one resource group. If these resources are always required to be hosted on the same machine, they should all be placed in the same resource group.

Every application needs to be defined as a resource in order to be managed and automated with Tivoli SA MP. Application resources are usually defined in the generic resource class IBM.Application. In this resource class, there are several attributes that define a resource, but at least three of them are application-specific:

StartCommand
StopCommand
MonitorCommand

These commands may be scripts or binary executables.

Setting up Tivoli SA MP with your DB2 environment

For configuration information to help you set up SA MP to work with your DB2 environment, see Configuring a clustered environment for high availability or search for "Tivoli System Automation" on the IBM Software Library web site (http://www.ibm.com/software/sw-library/).

Using Tivoli SA MP commands with the DB2 High Availability (HA) Feature

When you use the DB2 High Availability (HA) Feature, many DB2 commands can perform automatically the necessary cluster manager configurations for you if you have configured the instance for high availability using the db2haicu command.

In those environments, for example, if you initiate a db2stop command, the resource group is locked to prevent Tivoli SA MP from bringing the resource back online. Similarly, when you want to perform a takeover operation in a normal HADR takeover scenario, you can use the DB2 command TAKEOVER HADR and the database manager will automatically perform the related cluster manager configuration so that the HADR standby database can take over as a HADR primary database.

Note: As an alternative method to perform a takeover, you can use the SA MP command rgreq -o move but this command performs a forced takeover operation. In a maintenance scenario where you want to perform a normal non-forced takeover, you should use the DB2 command TAKEOVER HADR.

For the list of the DB2 database manager instance configuration and administration operations that perform related cluster manager configuration through SA MP, see Configuring a cluster automatically with the DB2 High Availability (HA) Feature.