Automatic Failover Without Requiring Network Storage or SAN
Failover is the process specifically associated with the cluster systems. Typically
it means when the Primary station of a cluster system dies, the Secondary
station is activated to take over the active duty of the Primary station.
ClusterReplica software monitors the systems in the cluster system and the
pre-defined services to determine if the cluster system is needed.
ClusterReplica SQL 3.1 binds two systems together directly. For this reason,
Failover can take place without the involvement of a network storage/SAN or any
type of independent disk array system. This
contrasts with Microsoft’s cluster system which requires such involvement.
Failover triggering events in ClusterReplica SQL 3.1
There are three situations that will trigger Failover:
- Receive no response during keep-alive period - The Secondary
station monitors the active state of the Primary station in a pre-set
duration of time. The default setting of the keep-alive period is 15
seconds. Users can make adjustments to this time period for ClusterReplica
to determine when to Exercise Failover
- Monitored services malfunction or fail to start - when any one of
the defined monitored services is detected in malfunction, failover will be
activated
- Public connection network adapter fails to function - when the
public connection to the Primary station fails due to either a network card
malfunction or the disconnection of the network cable, failover is activated
Back to ClusterReplica Home page
|
