The two operation modes for the system switchover facility are the monitor mode and the server mode. When operating in the monitor mode, only system failures are monitored. When operating in the server mode, both system and server failures are monitored. Also, system switchover can be performed more quickly in the server mode. The functional differences between the monitor mode and the server mode are listed in Table 25-8.

Table 25-8 Functional differences between the monitor mode and the server mode

Item or function		Monitor mode	Server mode
Failures that are monitored	System failures1	Yes	Yes
	Server failures2	No	Yes
Function that reduces system switchover time	User server standby3	No	Yes
	Rapid system switchover facility3	No	Yes
Standby-less system switchover facility	Standby-less system switchover (1:1) facility	No	Yes
	Standby-less system switchover (effects distributed) facility	No	Yes

Legend:

Yes: Is monitored or can be used.

No: Is not monitored or cannot be used.

¹ Errors such as those listed below are assumed to be system failures. However, the conditions for system failures are dependent on the cluster software specifications. For details, check the cluster software documentation or other applicable documentation.

• Hardware failures
• Operating system failures
• Power outages
• Cluster software failures
• System slowdowns

² Errors such as those listed below are assumed to be server failures.

• HiRDB abnormal termination (HiRDB/Parallel Server)
• HiRDB slowdown (or unit slowdown in the case of a HiRDB/Parallel Server)
• Database path error

³ This is a function that reduces the system switchover time. For details about user server hot standby and the rapid system switchover facility, see 25.18 Reducing system switchover time (user server hot standby, rapid system switchover facility).

Some cluster software cannot operate in the server mode. Cluster software that can be operated in the server mode is listed in Table 25-9.

Table 25-9 Cluster software that can be operated in the server mode

Cluster software	Monitor mode	Server mode
HA monitor	Yes	Yes
MC/ServiceGuard	Yes	Yes
VERITAS Cluster Server	Yes	Yes
Sun Cluster	Yes	No
HACMP	Yes	No
ClusterPerfect	Yes	No

Legend:

Yes: Can be operated in this mode.

No: Cannot be operated in this mode.

Note

In the Linux (EM64T) version, the system switchover facility in the server mode is not supported.

The products required to operate the system switchover facility in the server mode are listed in Table 25-10.

Table 25-10 Products required for operation in the server mode

Function	HiRDB Advanced High Availability	Hitachi HA Toolkit Extension
Server mode	--	Required#
User server hot standby	--	Required#
Rapid system switchover facility	--	Required#
Standby-less system switchover (1:1) facility	Required	Required#
Standby-less system switchover (effects distributed) facility	Required	Required#

Legend:

Required: This product is required for operation in the server mode.

--: Not required.

^# When the cluster software being used is HA monitor, Hitachi HA Toolkit Extension is not required.