Creating a Transaction Log (TLOG) in the MACHINES Section


	BEA Home \| Events \| Solutions \| Partners \| Products \| Services \| Download \| Developer Center \| WebSUPPORT
	http://www.oracle.com/technology/documentation/index.html \| Site Map \| Search \| PDF Files \| Contact \| Glossary

Tuxedo Documentation \| Setting Up a BEA Tuxedo Application \| Local Topics \| Previous Topic \| Next Topic \| Contents

To create a TLOG, complete the following tasks:

Create a Universal Device List (UDL).
Define transaction-related parameters in the MACHINES section.
Create a Domains transaction log.

Creating the UDL

The Universal Device List (UDL) is a map of the BEA Tuxedo filesystem. The UDL gets loaded into shared memory when an application is booted. The TLOG refers to a log in which information about transactions is kept until the transaction is completed. To create an entry in the UDL for the TLOG device, create a UDL on each machine using global transactions. (If the TLOGDEVICE is mirrored between two machines, it is unnecessary to do this on the paired machine.) The Bulletin Board Liaison (BBL) then initializes and opens the TLOG during the boot process.

To create a UDL, enter the following command before the application is booted:

tmadmin -c crdl -z config -b blocks

Note: The command fails if the device already exists.

The value of config must be the full pathname of the device on which you create the UDL. It should match the value of the TLOGDEVICE parameter in the MACHINES section of the configuration file. The value of blocks must be the number of blocks to be allocated on the device.

Note: If the value of blocks is less than the value of TLOGSIZE, you risk a performance degradation. Therefore, you should specify a value for blocks that is greater than that of TLOGSIZE. For example, if TLOGSIZE is specified as 200 blocks, specifying -b 500 does not cause a degradation.

For more information about storing the TLOG, see Installing the BEA Tuxedo System.

Defining Transaction-related Parameters in the MACHINES Section

To define a global transaction log (TLOG), you must set several parameters in the MACHINES section of the UBBCONFIG file.

For one of these parameters, TLOGDEVICE, you must manually create a device list entry for the TLOGDEVICE on each machine where a TLOG is needed. You can do this either before or after TUXCONFIG has been loaded, but you must complete this step before the system is booted.

The following table describes the transaction-related parameters in the MACHINES section.

Set This Parameter . . .	To Specify . . .
TLOGNAME	The name of the DTP transaction log for the machine.
TLOGDEVICE	The BEA Tuxedo filesystem that contains the DTP transaction log (TLOG) for the machine. If this parameter is not specified, it is assumed that there is no TLOG on the machine. The value may contain a maximum of 64 characters.
TLOGSIZEE	The size, in physical pages, of the TLOG file. The value must be between 1 and 2048; the default, 100. Assign a value that is large enough to hold the number of outstanding transactions on the machine at a given time. One transaction is logged per page. The default should be enough for most applications.
TLOGOFFSET	The offset, in pages, from the beginning of the TLOGDEVICE to the start of the VTOC that contains the transaction log for the machine.The value must be greater than or equal to 0, and less than the number of pages on the device. The default is 0. TLOGOFFSET is rarely necessary. However, if two VTOCs share the same device, or if a VTOC is stored on a device (such as a filesystem) that is shared with another application, you can use TLOGOFFSET to indicate a starting address relative to the address of the device.

Creating the Domains Transaction Log

Before starting a Domains gateway group, you must create a Domains transaction log. Specifically, you must create a Domains transaction log for the named local domain on the current machine (that is, the machine on which DMADM is running). To create a log, enter the following command:

dmadmin crdmlog crdlog -d local_domain_name

The command uses the parameters specified in the DMCONFIG file. This command fails if the named local domain is active on the current machine or if a log already exists. If a transaction log has not been created, the Domains gateway group creates one when that group starts.