IBM Streams 4.3.0

Guidelines for configuring Linux ulimit settings for IBM Streams

The default Linux user limit (ulimit) values might be too small for some IBM® Streams environments. Use these guidelines to ensure that your ulimit settings are sufficient for IBM Streams.

If the ulimit values are too small for your IBM Streams environment, issues can occur such as system startup, processing element (PE), and application development and submission failures. You can use ulimit settings to control the use of system resources.

There are two types of ulimit settings:
  • The hard limit is the maximum value that is allowed for the soft limit. Any changes to the hard limit require root access.

  • The soft limit is the value that Linux uses to limit the system resources for running processes. The soft limit cannot be greater than the hard limit.
The following hard and soft ulimit settings were used when IBM Streams was tested on Red Hat Enterprise Linux (RHEL), SUSE Linux Enterprise Server (SLES) (IBM Streams 4.3.1 only), or Community Enterprise Operating System (CentOS) systems:
  • max user processes value = 100000
  • open files value = 100000
  • pending signals value = 100000
Parent topic: Planning to install IBM Streams