When a checkpoint dump file is duplicated, even if full recovery using the system A file failed due to an error, full recovery can be performed using the file of the other system (system B).
- Initialization of a physical file
Before starting OpenTP1, create two physical files (one for system A and the other for system B) on the OpenTP1 file system, with the jnlinit command.
The physical files for system A or B must be created over several disks. If all the physical files of either system is created on a single disk when one-system operation is unavailable, error in the entire disk disables the system. The OpenTP1 system will go down, assuming that there is no file group available.
- Definition
Do not forget to specify jnl_dual=Y in the checkpoint dump service definition. The correspondence between a file group and the created physical files (for systems A and B) is specified with the jnladdpf definition command.
When a physical file is duplicated, one-system operation is available in case of an error. One-system operation can be enabled or disabled with the jnl_singleoperation operand in the checkpoint dump service definition.
For details of the checkpoint dump service definition, see the manual OpenTP1 System Definition.