The global journal service facility can use up to 16 different resource groups depending on the node to be archived or its service. One resource group is to be specified in one archive journal service definition.

The archive journal service definition specifies the correspondence among physical files, logical file groups that control the physical files, and element files.

A file group consists of logical files that are used by OpenTP1 to perform journal generation control. Swapping of journal files in online mode takes place on a file group basis. The user can specify 2-256 file groups for one resource group, giving a desired name to each file group. The name must not be duplicated, however.

Element files are logical files that are dispersed when the parallel access facility is used for archive journal files. Online-mode journal file access is distributed to element files, thus dispersing the load on disk.

To use the parallel access facility, the user must specify jnl_max_file_dispersion=2 or more and jnl_min_file_dispersion of the archive journal service definition. One file group can accommodate 2-8 element files, each given a user-selected name. (The name must not be duplicated, however.) Note that, since a unique number of dispersions is used for resource groups, the same number of element files must be specified for each file group.

When using no parallel access facility, the user need not specify element files. OpenTP1 perform processing as if one file group were one element file.

An archive journal file can be duplicated. To implement a duplicated file configuration, two physical files, one for system A and the other for system B, must be specified for one element file. Journals of the same contents are written in the two physical files. Duplication requires jnl_dual=Y to be specified in the archive journal service definition. In a duplicated file system, there may be the case where only one system can be used; jnl_singleoperation must be specified to select whether one-system operation is to be available or unavailable.

For a non-duplicated archive journal file configuration, one physical file is to be specified for one element file. Note that, since whether to duplicate is unique for resource groups, the same number of physical files must be specified for each element file.

Before starting OpenTP1, the user must execute the jnlinit command to create a physical file on the OpenTP1 file system. The physical file must have the same name as that specified in the archive journal service definition.

After the physical file is created, the correspondence between the physical file and the element file/file group/resource group must be specified in the archive journal service definition.

For the archive journal service definition, see the manual OpenTP1 System Definition.

For details about estimating the size of an archive journal file, see H.5 Estimating the size of an archive journal file.