The following table shows the site switchover methods that can be used when a disaster occurs at the main site.

Table 5-3 Site switchover methods that can be used when a disaster occurs at the main site

No.	Site switchover method	Main site		Remote site		Route
		Server machine	Hitachi disk array system	Server machine	Hitachi disk array system
1	Switching sites in the event of a disaster#	Disaster	Disaster	Normal operation	Normal operation	Normal operation
2		Disaster	Disaster	Normal operation	Normal operation	Error
3		Disaster	Disaster	Normal operation	Error	--
4	Cannot be switched over	Disaster	Disaster	Error	--
5		Disaster	Disaster	Disaster	Disaster
6		Disaster	Disaster	--	Paired

Legend:

Normal operation: A state in which neither an error nor a disaster has occurred, and indicates that all devices are functioning normally.

Error: An error has occurred in one or more of the devices.

Error in the Route column means that all transmission of Hitachi disk array system data has stopped between the sites.

Paired: Indicates that the Hitachi disk array system's paired logical volumes are being generated or re-synchronized.

Disaster: Indicates that none of the devices at the site are functioning because of a disaster.

--: Normal operation, Error, Paired, or Disaster

#: The detailed results of switching sites in the event of a disaster are described in 5.1.5 Results of switching sites in the event of a disaster.