Some Linux distributions, such as Redhat Enterprise Linux Server and CentOS 6.0 or later, set the default maximum number of user processes to 1024. This is considerably lower than the same parameter on older distributions. The default value of 1024 leads to some Java virtual machine memory errors when running multiple servers on a machine, because each Linux thread counts as a user process.

At startup, the PingDirectory server and its tools automatically attempt to raise the maximum user processes limit to 16,383 if the value reported by ulimit is less than that. If, for any reason, the server is unable to automatically set the maximum processes limit to 16,383, it displays an error message.

There are several ways to set the maximum user process limit.

  • Set the limit in /etc/security/limits.conf.

    Replace the (*) with the name of the user under which the software will run.

    * soft nproc 65535
    * hard nproc 65535
  • Set the NUM_USER_PROCESSES environment variable to 16383.
  • In the config/num-user-processes file, set NUM_USER_PROCESSES to 16383.