When you use the all synchronous method, update copying to the remote site is performed using synchronous copying. With synchronous copy, update processing is not complete at the main site until update processing at the remote site is completed (update processing at the main site waits for update processing at the remote site to be finished). Therefore, when the all synchronous copy method is used, updates at the main site are always mirrored at the remote site. This means that if the HiRDB at the main site fails due to a disaster or other calamity, HiRDB can be restarted and service can be resumed at the remote site in the same status as existed immediately before the failure.

However, because HiRDB at the main site pauses each time a file at the remote site is being updated, transaction processing at the main site is affected adversely.

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

Figure 8-16 Overview of the all synchronous method

Table 8-7 Processing method used when update copying to the remote site is performed (all synchronous method)

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