Preparing Linux systems for installation with a new DB2 Express database

Before you can install IBM® Business Process Manager, you must prepare your Linux operating system.

Complete the following steps on your Linux system before installing IBM Business Process Manager:

1. Because WebSphere® Application Server is a prerequisite of IBM Business Process Manager, complete all the required preparation steps in the Preparing Linux systems for installation topic in the WebSphere Application Server information center.
2. Ensure that you have administrative (root) privileges.
3. Increase the allowable stack size, number of open files, number of processes, and file size by adding the following lines to the end of the /etc/security/limits.conf file or changing the values if the lines already exist. In this example, user_name is the name of the user that runs WebSphere Application Server:

   # - stack - maximum stack size (KB)
   user_name soft stack 32768
   user_name hard stack 32768
   # - nofile - maximum number of open files
   user_name soft nofile 65536
   user_name hard nofile 65536
   # - nproc - maximum number of processes
   user_name soft nproc 16384
   user_name hard nproc 16384
   # - fsize - maximum file size
   user_name soft fsize 6291453
   user_name hard fsize 6291453

   Save and close the file, and log off and log in again. You can check the current maximum number of open files by using ulimit -n and the current maximum file size by using ulimit -f. The ulimit requirement is dynamically calculated at installation time and might need to be larger based on the options you select. For more information about this setting, run man limits.conf or see the topic Preparing the operating system for product installation in the WebSphere Application Server information center.
4. Check for the existence of a file named /etc/security/limits.d/90-nproc.conf or /etc/security/limits.d/20-nproc.conf, which overrides the nproc value set in the limits.conf file. If this file exists, edit it and set the same nproc values that you specified in limits.conf.
5. If you have previously installed and uninstalled DB2, ensure that the previous database entries in the /etc/services file have been deleted. For example, if the previous entry DB2_instance-name_suffix 50000/tcp still exists, the new installation will use the next available port, 50001, which might not work with your configuration. For more information, see Verifying port range availability in the DB2 information center.
6. Reboot the system.
7. Install the following packages for your operating system:

   Option	Description
   Red Hat Enterprise Linux 5	libXp-1.0.0-8 rpm-build-4.4.2-37.el5

   You can also install a later release of any of these packages if there are new packages as errata. If you have additional packages that are specific to your hardware, install them.
   The following command example shows how to use the default package manager on supported Linux distributions.

   • Red Hat Enterprise Linux 5:

     yum install libXp rpm-build 

8. Set the umask value to 077 using the following command:
   • umask 077
   The value 077 is the most restrictive value that IBM Business Process Manager will tolerate. You can optionally choose to set a less restrictive umask value for the following access levels:

   • 037 for read-only access for a group of human administrators and tools
   • 027 for read and write access for a group of human administrators and tools
   • 007 for read, write, and execute access for a group of human administrators and tools
9. On Red Hat Enterprise Linux 5 systems, disable SELinux, or set it to a permissive mode.
10. Restart the computer.
11. Complete the steps in Tuning Linux systems.
12. Ensure all servers involved are set to the same time. Use the same network time protocol for all servers on all cluster nodes, including application, support, and database clusters. A time mismatch will cause erratic behavior, including duplicate system tasks.