Preparing Linux systems for installation with a new Db2 database

Complete the following steps on your Linux system before installing Business Automation Workflow:

1. Because WebSphere® Application Server is a prerequisite of Business Automation Workflow, complete all the required preparation steps in the Preparing Linux systems for installation topic in the WebSphere Application Server documentation.
   Note: Some X11 libraries (specified in the previous link) are required for WebSphere Application Server whether you use GUI interfaces in Linux or not.
2. Check that you have administrative (root) privileges.
3. Increase the allowable stack size, number of open files, number of processes, and file size. Add the following lines to the end of the /etc/security/limits.conf file or if the lines already exist, change the values. 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 documentation.
4. Check for the existence of a file that is 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. Check for the existence of a file name /etc/profile, which overrides the nofile values set in the limits.conf file. If the ulimit -n values exist in the /etc/profile file, edit it and set the same nofile values that you specified in limits.conf.
6. If you have previously installed and uninstalled Db2®, check that the previous database entries in the /etc/services file are deleted. For example, if the previous entry DB2_instance-name_suffix 50000/tcp still exists, the new installation uses the next available port, 50001, which might not work with your configuration. For more information, see Verifying port range availability in the Db2 documentation
7. Restart the system.
8. Set the umask value to 077 using the following command:
   • umask 077

   The value 077 is the most restrictive value that Business Automation Workflow tolerates. You can choose to set a less restrictive umask value for the following access levels. This step is optional.

   • 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. Restart the computer.
10. Complete the steps in Tuning Linux systems .
11. Check whether all servers that are 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 causes erratic behavior, including duplicate system tasks.