IBM Spectrum Scale Sharing Nothing Cluster performance tuning guide has been posted and please refer to link before you doing the below change.
Note: If the cluster is not dedicated for Hadoop workloads, take the default value for the above configurations.
For Hadoop-like workloads, one JVM process can open a lot of files. Therefore, tune the ulimit values:
# add the following lines at the end of /etc/security/limits.conf
* soft nofile 65536
* hard nofile 65536
* soft nproc 65536
* hard nproc 65536
The default value is usually 32K. If you see the error â€śallocate memoryâ€ťor â€śunable to create new native threadâ€ť, you could try to increase kernel.pid_max by adding â€śkernel.pid_max=99999â€ť at the end of /etc/sysctl.conf and then â€śsysctl -pâ€ť.