Before starting OpenTP1, the user must issue the jnlinit command in order to create physical files in an OpenTP1 file system. The name of the physical file must be same as the physical file name in the journal service definition.

Once a physical file has been created, the correspondence of the physical file to a file group (a logical file used to manage a number of physical files), and the correspondence of the file group to the element files must be specified in the system journal service definition.

File groups are logical files that are used by OpenTP1 to manage journal generations. During online operation, swapping of journal files takes place on a file group basis. Users can specify from 2 to 256 file groups in the system journal service definition, and give them any name they wish. However, the name must be unique within the system journal service definition.

Element files are logical files that are dispersed when the parallel access facility is used for system journal files. During online mode, journal file access is distributed among the element files, thus distributing the load on the disk.

To use the parallel access facility, in the system journal service definition, a value of 2 or more must be specified for the jnl_max_file_dispersion operand, and a value must be specified for the jnl_min_file_dispersion operand. One file group can accommodate from 2 to 8 element files, each with an arbitrary user-defined name which must be unique within the system journal service definition. For the jnl_max_file_dispersion operand, specify the maximum number of element files in each file group. For the jnl_min_file_dispersion operand, specify the number of element files needed to ensure a basic level of parallel access even while an element file is inaccessible due to an error.

You do not need to specify element files if you do not intend to use the parallel access facility.

System journal files can be duplicated. This is done (before starting OpenTP1) by using the jnlinit command to create physical files for both systems A and B. Once the physical files have been created, jnl_dual=Y must be specified in the system journal service definition and the correspondences between file groups and the physical files for systems A and B must be specified. Additionally, the user must specify in the jnl_singleoperation operand of the system journal service definition whether or not one-system operation is to be made available in the event one of the systems becomes unavailable.

Journal files that have been used in online mode must be re-created if you subsequently change any of the following aspects of the OpenTP1 environment:

• The node_id operand in the system common definition
• The name of a file group specified by the -g option of the jnladdfg or jnladdpf definition command in the system journal service definition
• The definition file name of the system journal service definition

The message KFCA01240-E is output if you start OpenTP1 without first re-creating the journal files. In this case, you will be unable to use the affected journal files.

For details of system journal service definition, see the manual OpenTP1 System Definition.