You can test your Postfix resource hierarchy by initiating a manual switchover. This will simulate a failover of a resource instance from the primary server to the backup server.
Performing a Manual Switchover from the GUI
You can initiate a manual switchover from the LifeKeeper GUI by selecting Edit, then Resource, then finally In Service from the drop down menu. For example, an in service request executed on a backup server causes the application hierarchy to be placed in service on the backup server and taken out of service on the primary server. At this point, the original backup server is now the primary server and original primary server has now become the backup server.
If you execute the Out of Service request, the application is taken out of service without bringing it in service on the other server.
Performing a Manual Switchover from the Command-Line Interface
You can initiate a manual switchover from the LifeKeeper command-line interface by the following steps on the server:
- This specifies the last resource instance that the action will be performed on. “tag-name” are the information elements that may be used to describe the resources in the hierarchy, the name can be checked from LifeKeeper GUI, or “lcdstatus” command.
This specifies the resource action that will be performed. To bring the resource instance into service, specify restore, to take a resource out of service, specify remove.
Please refer to man pages of perform action for more details.
When the following failure occurs on the in service server, the Postfix Recovery Kit software performs Recovery:
- Failure in the Postfix resource
- Failure in IP resource relative to the Postfix resource
- Failure in file system resource relative to the Postfix resource
- Node Failure
When the primary server fails, the Postfix Recovery Kit software performs the following tasks:
- Brings the alias IP address into service on the backup server by bringing in service a logical interface on one of that server’s physical network interfaces
- Mounts the file system(s) on the shared disk on that server
- Starts the daemon processes related to Postfix
Since session context is lost following recovery, after the recovery, Postfix users must reconnect using exactly the same procedures they used to connect originally.