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 |
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.
2 Errors such as those listed below are assumed to be server failures.
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 |
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# |
# When the cluster software being used is HA monitor, Hitachi HA Toolkit Extension is not required.