Failover and failback, Failover – Dell PowerVault 775N (Rackmount NAS Appliance) User Manual
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1. Open a command prompt.
2. At the prompt, type:
c:\dell\util\cluster
3. In the cluster directory, run the NFSShareEnable.bat file.
Failover and Failback
This section provides information about the failover and failback capabilities of the Cluster Service.
Failover
When an individual application or user resource (also known as a cluster resource) fails on a cluster node, the Cluster Service
will detect the application failure and try to restart the application on the cluster node. If the restart attempt reaches a preset
threshold, the Cluster Service brings the running application offline, moves the application and its resources to another
cluster node, and restarts the application on the other cluster node. This process of automatically moving resources from a
failed cluster node to another healthy cluster node is called failover.
In order to failover and failback running applications, cluster resources are placed together in a group so the Cluster Service
can move the cluster resources as a combined unit. This process ensures that the failover and/or failback procedures
transfers all of the user resources as transparently as possible.
After failover, the Cluster Administrator can reset the following recovery policies:
Application dependencies
Application restart on the same cluster node
Workload rebalancing (or failback) when a failed cluster node is repaired and brought back online
Failover Process
The Cluster Service attempts to fail over a group when any of the following conditions occur:
The node currently hosting the group becomes inactive for any reason.
One of the resources within the group fails, and it is configured to affect the group.
Failover is forced by the System Administrator.
When a failover occurs, the Cluster Service attempts to perform the following procedures:
The group's resources are taken offline.
The resources in the group are taken offline by the Cluster Service in the order determined by the group's dependency
hierarchy: dependent resources first, followed by the resources on which they depend.