The node supervisor processes (NSUP) ensure the availability of HADB by exchanging “I’m alive” messages with each other. The NSUP executable files must have root privileges so they can respond as quickly as possible. The clu_nsup_srv process does not consume significant CPU resources, has a small footprint, and so running it with real-time priority does not affect performance.
The Java Enterprise System installer automatically sets the NSUP privileges properly, so you do not need to take any further action. However, with the standalone Application Server (non-root) installer, you must set the privileges manually before creating a database.
If NSUPs do not have the proper privileges, you might notice symptoms of resource starvation such as:
False network partitioning and node restarts, preceded by a warning “Process blocked for n seconds” in HADB history files.
Aborted transactions and other exceptions.
If NSUP cannot set the real-time priority errno is set to EPERM on Solaris and Linux. On Windows it issues the warning “Could not set real-time priority”. The error is written to the ma.log file, and the process continues without real-time priority.
Setting real-time priorities is not possible when:
HADB is installed in Solaris 10 non-global zones
PRIV_PROC_LOCK_MEMORY (allow a process to lock pages in physical memory) and/or PRIV_PROC_PRIOCNTL privileges are revoked in Solaris 10
Users turn off setuid permission
Users install the software as tar files (the non-root installation option for the Application Server)
Log in as root.
Change your working directory to HADB_install_dir/lib/server.
The NSUP executable file is clu_nsup_srv .
Set the file’s suid bit with this command:
chmod u+s clu_nsup_srv
Set the file’s ownership to root with this command:
chown root clu_nsup_srv
This starts the clu_nsup_srv process as root, and enables the process to give itself realtime priority.
To avoid any security impact, the real-time priority is set immediately after the process is started and the process falls back to the effective UID once the priority has been changed. Other HADB processes run with normal priority.