Added section for tuning configuration settings

docs/en/07-administration/07-chapter1.md

@@ -1052,3 +1052,144 @@ these properties in the [rundeck-config.properties](#rundeck-config.properties)
 |                         |overview instead of collapsing       |                    |
 |                         |empty groups. **Default: true**      |                    |
 +-------------------------+-------------------------------------+--------------------+
+
+## Customizing configuration for scale
+
+Note: This section is early in its development.
+
+### File descriptors
+
+The RunDeck server process opens a number of files during normal operation. These
+include system and java libraries, logs, and sockets. 
+Your system restricts the number of open file handles per process
+but these limitations can be adjusted.
+
+If your installation attempts to exceed the limit, you will see an error
+like the one shown below in your [service.log](#logs) file.
+
+    Too many open files 
+
+
+_On Linux nodes_
+
+List the current limit with the [ulimit](http://ss64.com/bash/ulimit.html) command:
+
+    ulimit -n
+
+If the limit is low (eg ``1024``) it should be raised.
+
+You can get the current number of open file descriptors used by the 
+RunDeck server process with [lsof](http://linux.die.net/man/8/lsof):
+
+    losf -p <rundeck pid> | wc -l
+
+Increase the limit for a wide margin. 
+Edit [/etc/security/limits.conf](http://ss64.com/bash/limits.conf.html) file
+to raise the hard and soft limits. Here they are raised to ``65535`` for 
+the "rundeck" system account:
+
+    rundeck hard nofile 65535
+    rundeck soft nofile 65535
+
+
+The system file descriptor limit is set in /proc/sys/fs/file-max. 
+The following command will increase the limit to 65535:
+
+    echo 65535 > /proc/sys/fs/file-max
+
+In a new shell, run the ulimit command to set the new level:
+
+    ulimit -n 65535
+
+The ulimit setting can be set in the [rundeckd](#rundeckd) 
+startup script, or [profile](#profile).
+
+Restart RunDeck.
+
+### Java heap size
+
+The ``rundeckd`` startup script sets initial and maximum heap sizes
+for the server process. For many installations it will be sufficient.
+
+If the Rundeck JVM runs out of memory, the following error occurs:
+
+    Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
+
+Heap size is governed by the following startup parameters: 
+``-Xms<initial heap size>`` and ``-Xmx<maximum heap size>``
+
+
+You can increase these by updating the RunDeck [profile](#profile). 
+To see the current values, grep the ``profile`` for 
+the Xmx and Xms patterns:
+
+* Launcher installs:
+
+        egrep '(Xmx|Xms)' $RDECK_BASE/etc/profile
+
+* RPM installs:
+
+        egrep '(Xmx|Xms)' /etc/rundeck/profile
+
+The default settings initialized by the installer 
+sets these to 1024 megabytes maximum
+and 256 megabytes initial:
+
+    export RDECK_JVM="$RDECK_JVM -Xmx1024m -Xms256m"
+
+_Sizing advice_
+
+Several factors drive memory usage in RunDeck:
+
+* User sessions
+* Concurrent threads
+* Concurrent jobs
+* Number of managed nodes
+
+For example, if your installation has dozens of active users 
+that manage a large environment (1000+ nodes), and has
+sufficient system memory, the following sizings might be more suitable:
+
+    export RDECK_JVM="$RDECK_JVM -Xmx4096m -Xms1024m -XX:MaxPermSize=256m"
+
+### Quartz job threadCount
+
+The maximum number of threads used by RunDeck for concurrent jobs 
+is set in the ``quartz.properties`` file. By default, this is set to ``10``.
+
+* RPM install: ``/var/lib/rundeck/server/exp/webapp/WEB-INF/classes/quartz.properties``
+* Launcher install: ``$RDECK_BASE/server/exp/webapp/WEB-INF/classes/quartz.properties``
+
+To change the maximum threadCount modify this file and alter the line:
+
+    org.quartz.threadPool.threadCount = 20
+
+Set the threadCount value to the max number of threads you want to run concurrently.
+
+Please refer to the Quartz site for detailed information:
+[Configuration - Thread Pool](http://www.quartz-scheduler.org/docs/1.x/configuration/ConfigThreadPool.html)
+
+### JMX instrumentation
+
+You may wish to monitor the internal operation of your RunDeck server via JMX.
+
+JMX provides introspection on the JVM, the application server, 
+and classes all through a consistent interface. 
+These various components are exposed to the management console 
+via JMX managed beans — MBeans for short.
+
+_Note_: For more background information on JMX, see 
+"[Java theory and practice: Instrumenting applications with JMX.](http://www.ibm.com/developerworks/library/j-jtp09196/)". 
+
+Enable local JMX monitoring by adding the ``com.sun.management.jmxremote``
+flag to the startup parameters in the [profile](#profile).
+
+    export RDECK_JVM="$RDECK_JVM -Dcom.sun.management.jmxremote"
+
+You use a JMX client to monitor JMX agents. 
+This can be a desktop GUI like JConsole run locally.
+
+    jconsole <rundeck pid>
+
+For instructions on remote JMX monitoring for Grails, Spring and log4j see:
+[Grails in the enterprise](http://www.ibm.com/developerworks/java/library/j-grails12168/index.html).