How to Create a TLOG Device


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To create distributed transaction processing, you must have created a global transaction log (TLOG) on each participating machine. To define a TLOG, complete the following steps.

You must first set several parameters in the MACHINES section of the configuration file: TLOGDEVICE, TLOGOFFSET, TLOGNAME, and TLOGSIZE.
You must also create a universal device list entry (UDL) for the TLOGDEVICE on each participating machine. (You can do this task before or after loading tuxconfig, but you must do so before booting the system.) To create an entry in the UDL for the TLOG device, invoke tmadmin -c on the MASTER machine with the application inactive. (The -c option invokes tmadmin in configuration mode.)
Enter the command:
```
crdl -z config -b blocks
```
where -z config specifies the full pathname for the device on which the UDL should be created (that is, where the TLOG will reside) and -b blocks specifies the number of blocks to be allocated on the device. The value of config should match the value of the TLOGDEVICE parameter in the MACHINES section. The blocks must be larger than the TLOGSIZE. If -z is not specified, the value of config defaults to the value of the variable FSCONFIG (which points to the application's databases).
Repeat steps 1 and 2 on each machine in your application that will use global transactions.

If the TLOGDEVICE is mirrored between two machines, step 4 is not required on the paired machine. To be recoverable, the TLOG should reside on a device that can be mirrored. Because the TLOG is too small (typically, 100 pages) to warrant the allocation of a whole disk partition, the TLOG is commonly stored on the same raw disk slice as the BEA Tuxedo /Q database.