The Tuner recommends server settings to suit the needs of your Enterprise Server deployment. It helps you reach an optimal configuration. Finer tuning might be needed in case of specific requirements. The Tuner performs static analysis of Enterprise Server resources and throughput requirements. No dynamic inspection of the system is performed.
The Tuner accommodates both homogeneous and nonhomogeneous clusters. Homogeneity is based on the following criteria: operating system, hardware, physical memory, and cores (logical CPUs). For homogeneous clusters, all criteria match for all machines where the cluster's component instances run. For nonhomogeneous clusters, these values differ. For nonhomogeneous clusters, you should start with pessimistic values and increase these values for specific component instances that run on more powerful or resourceful hardware.
System properties change settings for individual server instances within a cluster. The Tuner sets some system properties. For more information about system properties, see the following documentation:
Before tuning a cluster, ensure that all instances are running so the tuner can gather important data for calculating the tunable settings.
To use the Tuner, follow these steps:
Select the Tuner node in the left pane of the Admin Console.
Provide the requested information. If necessary, consult your system administrator.
Configuration to Tune — Select the name of the server or cluster from the drop-down list.
Number of Cores — Specify the number of logical CPUs (also known as processor threads) available per machine. The default is 1.
You don't need to specify the total number of CPUs on the machine, only the number you want to allocate for use by each Enterprise Server instance running on it.
On a Sun SPARC Enterprise T5440 (http://www.sun.com/servers/coolthreads/t5440/), the number of logical CPUs (or processor threads) is returned by a command such as psrinfo. A Sun SPARC Enterprise T5440 can have up to 256 processor threads. For more information, consult your hardware vendor's data sheet.
Maximum Heap Memory Available — Specify the size of the heap memory for the Enterprise Server's JVM server instance. The default is 1024 MB. The specified value for heap memory may not be applied if the tuner determines that it is not optimal.
Allocation Time for Database Access — Specify that the allocation time is Low (0% - 10%), Medium (10% - 20%), or High (>= 20%). The default is Medium.
This is the time in the database tier spent by the primary application deployed on the instance or cluster being tuned. If you have multiple applications deployed on the cluster, this should be the sum of the time spent in the database tier by all applications. You should also take into account the time spent per web or EJB request.
Garbage Collection Strategy — Specify either Maximum Peak Throughput (Higher GC Pause) or Low GC Pause (Lower Peak Throughput). The default is Maximum Peak Throughput.
This strategy determines what happens to garbage collection in the JVM. Obviously garbage collection should take minimal time, but this may not always be possible. The Enterprise Server's JVM can be configured to have many short GC pauses or a small number of relatively longer GC pauses. When a small number of GC pauses is your strategy, the throughput is generally greater, with 1 – 2% of requests experiencing latency.
Disable Security Manager? — Specify whether to disable the Java Platform Security Manager. Disabling the security manager may improve performance but may decrease system security. The default is Yes.
Disable Access Logger? — Specify whether to disable access logging. Disabling access logging may improve performance but removes some system information. The default is Yes.
Running on Sun's CoolThreads (Niagara) Server? — Check this box if the server instances are running on a Sun server with CoolThreadsTM technology. The default is No. For more information, see http://www.sun.com/servers/index.jsp?cat=SunCoolThreadsServers&tab=3.
Select the Next button.
Read the table of proposed changes carefully.
If you wish to make only some of the changes, note the text in the Current Setting, Proposed Setting, and To Manually Apply columns for the changes you wish to make.
For example, if the change adds or removes a JVM option, the option is displayed in the Current Setting or Proposed Setting column, and the following text is displayed in the To Manually Apply column:
Go to the JVM Settings page for the configuration, select the JVM Options tab, select the Add JVM Option button, and enter the JVM option. Or use one of these commands: asadmin create-jvm-options or asadmin delete-jvm-options
For more information about the asadmin commands referred to in the To Manually Apply column, see the Sun GlassFish Enterprise Server 2.1 Reference Manual.
Select one of the buttons to confirm or cancel the changes.
To accept all the changes, select Confirm.
To reject all the changes, select Cancel.
If you selected Cancel in step 6, manually apply any changes you found in step 5.
For example, to remove the -Xmx512m option, use the following asadmin command. Note that the dash must be escaped with a backslash and the option must be quoted.
asadmin delete-jvm-options "\-Xmx512m"
Restart each server instance or cluster that uses the configuration you tuned.
If you add server instances to a cluster, you should retune the configuration for that cluster.