When you use the hybrid method, update copying to the remote site is performed as follows:

• Update copying of database files is performed using asynchronous copying
• Update copying of system files is performed using synchronous copying

System logs and other files containing information needed to recover the database are copied to the remote site with synchronous copying, so their synchronization is guaranteed. This means that if the HiRDB at the main site fails due to a disaster, the HiRDB at the remote site can be restarted in the same status that the HiRDB at the main site was in immediately preceding the failure. The hybrid method is designed for use mainly in large-scale systems.

Asynchronous copying is then used for recoverable database files, thus reducing the severity of the adverse effects on transaction performance compared with the all synchronous method.

Reference note

Although the hybrid method provides the advantages of both the all synchronous method and all asynchronous method, operation is more difficult than under the other two methods.

The following figure provides an overview of the hybrid method, and the table below it shows the processing methods used with the hybrid method when update copying to the remote site is performed.

Figure 8-18 Overview of the hybrid method

Table 8-9 Processing methods used when update copying to the remote site is performed (hybrid method)

Files that are copied to the remote site		Processing method used for update copying
Database files		Asynchronous copy
System files	System log files	Synchronous copy
	Synchronization point dump files
	Status files