Tuesday, 26 August 2014

Guidelines for setting ulimits (WebSphere Application Server) - includes RHEL 6 updates


This document describes various ways to set ulimit values on UNIX and Linux operating systems as well as information that pertains to WebSphere Application Server

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Global settings are set in the file /etc/security/limits.conf.
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On Red Hat Enterprise Linux 6, why are my settings for nproc (ulimit -u) not being honored. Red Hat Enterprise Linux 6 has introduced a new configuration file, addressed in a bug report, ( /etc/security/limits.d/90-nproc.conf ) that overrides the nproc setting in the limits.conf. This file contains a line for nproc configured with a soft limit of 1024. 

*          soft    nproc     1024 

The rationale for this was to prevent fork bombs from occurring, To keep using the limits.conf for your nproc ulimit settings, you would need to comment this line out by making the first character on the line a hash/pound symbol. 

#*          soft    nproc     1024
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Guidelines for setting ulimits (WebSphere Application Server)

For the record, this was the exception that led me to this particular document: -

WARNING: Current system has detected a lower level of ulimit open files setting than the recommended value of 8192. Increase the ulimit open files value to minimum value of 8192 and re-start the installation.

Shutdown your installer. If you are a root user open a command prompt and issue ulimit -n 8192 and then restart the installer. If you are a non-root user, work with your system administrator to increase your ulimit -n 8192 and then restart the installer.
 

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