ORB properties and file descriptor settings

Tuning considerations include Object Request Broker (ORB) properties and file descriptor settings.

ORB properties

The ORB is used by WebSphere® eXtreme Scale to communicate over a TCP stack. The necessary orb.properties file is in the java/jre/lib directory. For a heavy load of large objects, enable ORB fragmentation by specifying the following setting:
  com.ibm.CORBA.FragmentSize=<right size>
Prevent ThreadPool growth by specifying the following setting:
com.ibm.CORBA.ThreadPool.IsGrowable=false
Set proper timeouts to avoid excess threads in an abnormal situation by specifying the following settings:
  • com.ibm.CORBA.RequestTimeout
  • com.ibm.CORBA.ConnectTimeout
  • com.ibm.CORBA.FragmentTimeout

File descriptor

UNIX® and Linux® systems there is a limit to the number of open files allowed per process. The operating system specifies the number of open files permitted. If this value is set too low, a memory allocation error will occur on AIX®, and too many files opened are logged.

In the UNIX system terminal window, set this value higher than the default system value. For large SMP machines with clones, set to unlimited.

For AIX configurations set this value to -1 (unlimited) with the command ulimit -n -1.

For Solaris configurations set this value to 16384 with the command ulimit -n 16384.

To display the current value use the command ulimit –a.