On some Linux distributions (Redhat Enterprise Linux Server/CentOS 6.0 or later), the default maximum number of user processes is set to 1024, which is considerably lower than the same parameter on older distributions (e.g., RHEL/CentOS 5.x). The default value of 1024 leads to some JVM memory errors when running multiple servers on a machine due to each Linux thread being counted as a user process.
/etc/security/limits.conf. For example:
* soft nproc 65535 * hard nproc 65535
The (*) can be replaced with the name of the user under which the software will run. These
settings can also be manually configured by setting the
NUM_USER_PROCESSES environment variable to 16383 or by setting the same
variable in a file named config/num-user-processes.