ORB properties

[Version 8.6 and later] (Deprecated)Object Request Broker (ORB) properties modify the transport behavior of the data grid. These properties can be set with an orb.properties file, as settings in the WebSphere® Application Server administrative console, or as custom properties on the ORB in the WebSphere Application Server administrative console.

Deprecated: The Object Request Broker (ORB) is deprecated. If you were not using the ORB in a previous release, use IBM® eXtremeIO (XIO) for your transport mechanism. If you are using the ORB, consider migrating your configuration to use XIO.

orb.properties

The orb.properties file is in the java/jre/lib directory. When you modify the orb.properties file in a WebSphere Application Server java/jre/lib directory, the ORB properties are updated on the node agent and any other Java virtual machines (JVM) that are using the Java runtime environment (JRE). If you do not want this behavior, use custom properties or the ORB settings WebSphere Application Server administrative console.

Default WebSphere Application Server settings

WebSphere Application Server has some properties defined on the ORB by default. These settings are on the application server container services and the deployment manger. These default settings override any settings that you create in the orb.properties file. For each described property, see the Where to specify section to determine the location to define the suggested value.

File descriptor settings

For UNIX and Linux® systems, a limit exists for the number of open files that are allowed per process. The operating system specifies the number of open files permitted. If this value is set too low, a memory allocation error occurs 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 unlimited with the command: ulimit -n unlimited.

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

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

Baseline settings

The following settings are a good baseline but not necessarily the best settings for every environment. Understand the settings to help make a good decision on what values are appropriate in your environment.

com.ibm.CORBA.RequestTimeout=30
com.ibm.CORBA.ConnectTimeout=10
com.ibm.CORBA.FragmentTimeout=30
com.ibm.CORBA.LocateRequestTimeout=10
com.ibm.CORBA.ThreadPool.MinimumSize=256
com.ibm.CORBA.ThreadPool.MaximumSize=256
com.ibm.CORBA.ThreadPool.IsGrowable=false
com.ibm.CORBA.ConnectionMultiplicity=1
com.ibm.CORBA.MinOpenConnections=1024
com.ibm.CORBA.MaxOpenConnections=1024
com.ibm.CORBA.ServerSocketQueueDepth=1024
com.ibm.CORBA.FragmentSize=0
com.ibm.CORBA.iiop.NoLocalCopies=true
com.ibm.CORBA.NoLocalInterceptors=true
com.ibm.CORBA.SocketWriteTimeout=30

Property descriptions

Timeout Settings

The following settings relate to the amount of time that the ORB waits before giving up on request operations. Use these settings to prevent excess threads from being created in an abnormal situation.

Request timeout

Property name: com.ibm.CORBA.RequestTimeout

Valid value: Integer value for number of seconds.

Suggested value: 30

Where to specify: WebSphere Application Server administrative console

Description: Indicates how many seconds any request waits for a response before giving up. This property influences the amount of time a client takes to fail over if a network outage failure occurs. If you set this property too low, requests might time out inadvertently. Carefully consider the value of this property to prevent inadvertent timeouts.

Connect timeout

Property name: com.ibm.CORBA.ConnectTimeout

Valid value: Integer value for number of seconds.

Suggested value: 10

Where to specify: orb.properties file

Description: Indicates how many seconds a socket connection attempt waits before giving up. This property, like the request timeout, can influence the time a client takes to fail over if a network outage failure occurs. In general, set this property to a smaller value than the request timeout value because the amount of time to establish connections is relatively constant.

Fragment timeout

Property name: com.ibm.CORBA.FragmentTimeout

Valid value: Integer value for number of seconds.

Suggested value: 30

Where to specify: orb.properties file

Description: Indicates how many seconds a fragment request waits before giving up. This property is similar to the request timeout property.

Socket write timeout

Property name: com.ibm.CORBA.SocketWriteTimeout

Valid value: Integer value for number of seconds.

Suggested value: 30

Where to specify: orb.properties file

Description: Indicates how many seconds a socket write waits before giving up. This property is similar to the request timeout property.

Thread Pool Settings

These properties constrain the thread pool size to a specific number of threads. The threads are used by the ORB to spin off the server requests after they are received on the socket. Setting these property values too low results in an increased socket queue depth and possibly timeouts.

Connection multiplicity

Property name: com.ibm.CORBA.ConnectionMultiplicity

Valid value: Integer value for the number of connections between the client and server. The default value is 1. Setting a larger value sets multiplexing across multiple connections.

Suggested value: 1

Where to specify: orb.properties file

Description: Enables the ORB to use multiple connections to any server. In theory, setting this value promotes parallelism over the connections. In practice, performance does not benefit from setting the connection multiplicity. Do not set this parameter.

Open connections

Property names: com.ibm.CORBA.MinOpenConnections, com.ibm.CORBA.MaxOpenConnections

Valid value: An integer value for the number of connections.

Suggested value: 1024

Where to specify: WebSphere Application Server administrative console

Description: Specifies a minimum and maximum number of open connections. The ORB keeps a cache of connections that have been established with clients. These connections are purged when this value is passed. Purging connections might cause poor behavior in the data grid.

Is Growable

Property name: com.ibm.CORBA.ThreadPool.IsGrowable

Valid value: Boolean; set to true or false.

Suggested value: false

Where to specify: orb.properties file

Description: If set to true, the thread pool that the ORB uses for incoming requests can grow beyond what the pool supports. If the pool size is exceeded, new threads are created to handle the request but the threads are not pooled. Prevent thread pool growth by setting the value to false.

Server socket queue depth

Property name: com.ibm.CORBA.ServerSocketQueueDepth

Valid value: An integer value for the number of connections.

Suggested value: 1024

Where to specify: orb.properties file

Description: Specifies the length of the queue for incoming connections from clients. The ORB queues incoming connections from clients. If the queue is full, then connections are refused. Refusing connections might cause poor behavior in the data grid.

Fragment size

Property name: com.ibm.CORBA.FragmentSize

Valid value: An integer number that specifies the number of bytes. The default is 1024.

Suggested value: 0

Where to specify: orb.properties file

Description: Specifies the maximum packet size that the ORB uses when sending a request. If a request is larger than the fragment size limit, then that request is divided into request fragments that are each sent separately and reassembled on the server. Fragmenting requests is helpful on unreliable networks where packets might need to be resent. However, if the network is reliable, dividing the requests into fragments might cause unnecessary processing.

No local copies

Property name: com.ibm.CORBA.iiop.NoLocalCopies

Valid value: Boolean; set to true or false.

Suggested value: true

Where to specify: WebSphere Application Server administrative console, Pass by reference setting.

Description: Specifies whether the ORB passes by reference. The ORB uses pass by value invocation by default. Pass by value invocation causes extra garbage and serialization costs to the path when an interface is started locally. By setting this value to true, the ORB uses a pass by reference method that is more efficient than pass by value invocation.

No Local Interceptors

Property name: com.ibm.CORBA.NoLocalInterceptors

Valid value: Boolean; set to true or false.

Suggested value: true

Where to specify: orb.properties file

Description: Specifies whether the ORB starts request interceptors even when making local requests (intra-process). The interceptors that WebSphere eXtreme Scale uses are for security and route handling are not required if the request is handled within the process. Interceptors that go between processes are only required for Remote Procedure Call (RPC) operations. By setting the no local interceptors, you can avoid the extra processing that using local interceptors introduces.

Attention: If you are usingWebSphere eXtreme Scale security, set the com.ibm.CORBA.NoLocalInterceptors property value to false. The security infrastructure uses interceptors for authentication.