If you use the all synchronous method, update copying to the remote site is performed using synchronous copy. With synchronous copy, the main site is updated after updating at the remote site is completed (updating at the main site waits for updating at the remote site to be completed). Therefore, when you use the all synchronous method, content updated at the main site is always imported into the remote site. Therefore, even if a disaster abnormally terminates the HiRDB system at the main site, you can continue services by restarting HiRDB at the remote site and be assured that your HiRDB system is in the state that it was in immediately before the abnormal termination.

However, when a file (update-copy target files) is updated at the main site, the main site waits until that update is imported to the remote site. Consequently, transaction performance at the main site may be adversely impacted.

The figure below provides on overview of the all synchronous method. The table that follows shows the processing method used for copying the update to the remote site (using the all synchronous method).

Figure 1-2 Overview of the all synchronous method

Table 1-2 Processing method used for update copying to the remote site (using the all synchronous method)

Files 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