• Because messages are sent over interprocess communication (IPC) queues, the advantage of local data compression is that it results in lower utilization of IPC resources.
• Because messages are sent over a network, the advantage of remote data compression is that it results in lower utilization of network bandwidth.If you decide to use data compression, you must set the CMPLIMIT parameter in the MACHINES section of the configuration file, as follows:The strings that make up the value of this parameter specify the threshold message size for messages bound to remote processes (string_value1) and local processes (string_value2). Only the first string is required. The default for both strings is the value of the MAXLONG parameter.In addition, you have the option of setting the TMCMPPRFM parameter to establish an appropriate balance between compression and CPU performance. Higher and slower compression results in more efficient network bandwidth; lower but faster compression yields less CPU utilization.
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2. (Optional step) Set the TMCMPPRFM environment variable. The value of TMCMPPRFM must be a single digit between 1 and 9; the default is 1.For more information on setting the TMCMPPRFM variable, refer to tuxenv(5) in the File Formats, Data Descriptions, MIBs, and System Processes Reference.You can designate a compression threshold for messages: any messages larger than the threshold you specify are compressed. To designate a compression threshold, set the CMPLIMIT parameter. For instructions, see “How to Set the Compression Level” on page 4‑2.
• Consider using remote data compression if your sites are running Oracle Tuxedo release 4.2.1 or later. Your setting depends on the speed of your network. You may want to assign different settings, for example, to an Ethernet network (which is a high-speed network) and an X.25 network (which is a low-speed network).
• For a high-speed network, consider setting remote data compression to the lowest limit for file transfers generated by the Oracle Tuxedo system. (See the note about file transfers provided later in this list.) In other words, compress only messages that are large enough to be candidates for file transfer on either the sending site or the receiving site. Note that each machine in an application may have a different limit. If this is the case, choose the lowest limit possible for each machine.
• For a low-speed network, consider setting remote data compression to zero on all machines; that is, compress all application and system messages.
• Consider using local data compression for sites running Oracle Tuxedo release 4.2.1 or later, even if they are interoperating with pre-release 4.2.1 sites. This results in lower utilization of IPC resources. This setting also enables you to avoid file transfers in many situations that might otherwise require a transfer and, when file transfers cannot be avoided, this setting greatly reduces the size of the files used. For more information, refer to “Message Queues and Messages” in Installing the Oracle Tuxedo System.
• DMCONFIG(5) in the File Formats, Data Descriptions, MIBs, and System Processes Reference
• tuxenv(5) in the File Formats, Data Descriptions, MIBs, and System Processes Reference
• If load balancing is turned on (that is, if LDBAL is set to Y in the RESOURCES section of the application configuration file), the Oracle Tuxedo system attempts to balance requests across the network. Because load information is not updated globally, each site has a unique view of the load at remote sites.Use the NETLOAD parameter in the MACHINES section of the configuration file (or the TMNETLOAD environment variable) to force more requests to be sent to local queues. The value of this parameter is a number that is added to the load for remote queues, so the remote queues appear to have more work than they do. As a result, even if load balancing is turned on, local requests are sent to local queues more often than to remote queues.As an example, assume servers A and B offer a service with load factor 50. Server A is running on the same machine as the calling client (local), and server B is running on a different machine (remote). If NETLOAD is set to 100, approximately three requests will be sent to A for every one sent to B.
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Note: For detailed information about factory-based routing for a distributed Oracle Tuxedo CORBA application, refer to the Scaling, Distributing, and Tuning CORBA Applications guide.Figure 4‑1 illustrates this process.Figure 4‑2 illustrates this process.
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• Chapter 9, “Distributing ATMI Applications Across a Network,”in Setting Up an Oracle Tuxedo Application
• Chapter 10, “Creating the Configuration File for a Distributed ATMI Application,”in Setting Up an Oracle Tuxedo Application
• Chapter 11, “Setting Up the Network for a Distributed Application,” in Setting Up an Oracle Tuxedo ApplicationTo change configuration parameters while your application is running, run the tmconfig(1) command. This command is a shell-level interface to the Oracle Tuxedo System Management Information Base (MIB).Using tmconfig, you can browse and modify the TUXCONFIG file without bringing down your system. For example, you can add new components, such as machines and servers, while your application is running.
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• MIB(5) in the File Formats, Data Descriptions, MIBs, and System Processes Reference
• TM_MIB(5) in the File Formats, Data Descriptions, MIBs, and System Processes Reference
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