Application Server Fail-over Procedure

Owned by Emma Paton (Unlicensed)
Aug 10, 2017
2 min read

The Remote Sampler system has two identical setups on two separate application servers, only one of which is in operation at any one time. The process described in this section outlines the steps that are required to switch the live system from one application server to the other.

For the purposes of this description, Server A will play the role of the currently live application server that is suffering from a technical problem and Server B is the backup server to which we wish to switch all live Remote Sampler operations.

The first step in the failover process is to log on to the Server A and deactivate the currently live services if they are still running. This can be done by navigating to the initial installation folder for all of the Remote Sampler services using the Windows Explorer and double-clicking the StopServices.lnk shortcut as shown in the screenshot below.

 

Once this shortcut has been run, you can check that the services are no longer running by opening the Windows Services Manager and checking the Status column by each of the CSols services as shown in the image below.

 

With the services deactivated, log out of Server A.

Connect to the live production LabCache database using Microsoft SQL Server Management Studio and navigate to the LcFailover table. This contains an entry for each of the application servers that are currently configured. The entry for Server A will have a value of True in the column for IsCurrentlyLive. Set this to False and perform the inverse for the entry in the table for Server B.

 

With the database configuration adjusted to shift the configuration of the live application server to Server B, all that needs to be done to get the system fully up and running is to activate the services on Server B. Connect to Server B and use the StartServices.Lnk shortcut in the Remote Sampler installation folder to reactivate all the services. Once again, you can check that the services have been reactivated successfully by opening the Windows Services Manager and checking the values in the Status column for the CSols services.

If you encounter any difficulty with getting any of the processes restarted, please contact CSols support.