Answer: On some operating systems the default amount of physical memory that can be pinned/locked by a user application is set to a low value and must be explicitly increased. A value recommended by Intel is 90% of the physical memory. Therefore, for a system with 8 GB of memory the following should be added to the /etc/security/limits.conf file on all machines in the cluster: soft memlock 7500000 hard memlock 7500000 The computer must be re-booted after making this change. If using the PBS job scheduler try putting “ulimit -n unlimited” directly in the pbs_mom startup script, and let PBS reload the pbs_moms. You may need to contact the person who is responsible for the PBS configuration.