The following table lists criteria helpful for deciding which system switchover facility to use.

Table 26-9 System switchover facility application criteria

Importance	Standby system switchover facility	Standby-less system switchover (1:1) facility	Standby-less system switchover (effects distributed) facility
Transaction performance	Excellent	Poor	Good
	Maintains performance even when an error occurs. Guarantees the same throughput as during normal operations.	Load from alternate processing when an error occurs might impact processing performance. Load concentration on certain units reduces system throughput.	Load from alternate processing when an error occurs might impact processing performance. Load distribution is used to minimize system throughput degradation.
Resource requiremen	Poor	Excellent	Excellent
	Needs standby server machines or system resources for standby system units.	Does not need standby server machines or system resources for standby system units.	Does not need standby server machines or system resources for standby system units.
Handling of a series of errors	Excellent	Poor	Excellent
	Can handle a series of errors based on linkage with cluster software (only when IP addresses are inherited, and not when the rapid system switchover facility is used).	Cannot handle a series of errors because there is only one fixed alternate server.	Can handle a series of errors based on linkage with cluster software.

Legend:

Excellent: Applicability is excellent.

Good: Applicability is good.

Poor: Applicability is poor.

The following table indicates whether each system switchover facility can be used when another system switchover facility is already being used for another unit in the same system.

Table 26-10 Usability of each system switchover facility when another system switchover facility is already being used for another unit in the same system

Facility already being used	Usability of the standby system switchover facility	Usability of the standby-less system switchover (1:1) facility	Usability of the standby-less system switchover (effects distributed) facility
Standby system switchover facility	Y	Y	Y
Standby-less system switchover (1:1) facility	Y	Y	N
Standby-less system switchover (effects distributed) facility	Y	N	Y#

Legend:

Y: Can be used.

N: Cannot be used.

#: Only one HA group can be used at the switching destination.