IBM DB2 9.7 Advanced Administration Cookbook: Over 100 recipes focused on advanced administration tasks to build and configure powerful databases with IBM DB2 book and ebook

For this recipe (and almost all recipes in this book), we will use two servers running Red Hat Enterprise Linux Server x64 release 5.5 (Tikanga), named nodedb21 and nodedb22. The hostnames are optional, but our recommendation is to set up an identical environment to avoid confusion during reading and applying the recipes.

As install location for the IBM DB2 9.7 Enterprise Server Enterprise software product, we will use the directory /opt/ibm/db2/V9.7 on nodedb21. On nodedb22, we will install DB2 Client software to location /opt/ibm/db2/V9.7_clnt. The instance owner will be db2inst1 on nodedb21 and db2clnt1 as client instance owner on nodedb22. Also, on nodedb21, we will create a second instance owner user named db2inst2, to demonstrate how to create an instance manually.

The default method to create an instance is during the IBM DB2 9.7 Enterprise Server Edition software installation. The other possible option is to use the db2icrt command.

In Linux and Unix, every instance is created under a dedicated user, called the instance owner. To create an instance in Linux and UNIX you have to be the root user; on these platforms, we are limited to one instance per user. On Microsoft Windows platforms, you may have more than one instance created under the same user.

Usually, if you set up the software in graphical mode you do not have to create the users manually—you can do this using the wizard. In our recipes, we want to reuse the same groups (db2iadm1 and db2fadm1) for the non-partitioned and the multipartitioned instance and database setup. For the multipartitioned setup we will have the same groups defined on both servers; because we have to deal with security regarding permissions, here, we should create the groups with the same group ID (GID):

In Linux or Unix, when an instance is created, the db2icrt command builds up under the instance owner home directory, the sqllib directory, as a collection of symbolic links pointing to the IBM DB2 software installation home directory. If you want to see what is executing db2icrt in the background, you need to include the –d option to enable debug mode. This explains what happens behind the scenes for the steps mentioned earlier. Usually, this switch is used for detailed diagnostics, and should be activated at the request of IBM support.

Almost all files and directories from sqllib directory are symbolic links to the corresponding installation path (DB2HOME). A short listing inside sqllib directory looks like this:

[db2inst1@nodedb21]/home/db2inst1/sqllib>symlinks -v .
other_fs: /home/db2inst1/sqllib/map -> /opt/ibm/db2/V9.7/map
other_fs: /home/db2inst1/sqllib/bin -> /opt/ibm/db2/V9.7/bin
other_fs: /home/db2inst1/sqllib/ruby64 -> /opt/ibm/db2/V9.7/dsdriver/ruby64

On MS Windows platforms, the db2icrt command creates a service. The binaries are actually copied and a service associated with the instance is created.

On a generic Windows machine we'll create an instance named db2win. Initially, the associated service has the status set to stopped and the startup type set to manually. If you want the service to start automatically at system boot, you have to change its startup type to automatic.

To create instance db2win, execute the following command under a privileged user:

C:\Windows\system32>db2icrt db2win
DB20000I  The DB2ICRT command completed successfully.

To find the associated Windows service with db2win instance, execute the following command:

C:\Windows\system32>sc query state= all  | findstr "DB2WIN"
SERVICE_NAME: DB2WIN
DISPLAY_NAME: DB2 - DB2COPY1 - DB2WIN
C:\Windows\system32>

The db2isetup graphical tool might be used also for creating instances; this tool is available only on the Linux and Unix platforms.

On Linux and Unix you have the possibility to create a non-root type instance using the installer. You are limited to only one non-root instance per server.