The Assured Recovery option enables you to perform a full transparent test of the recoverability of your data on the Replica server. The Replica server that is tested is the one that would take over the production server if it will be down. The Assured Recovery option is a true test of the actual server, applications and actions that will be required in the event the Replica server will have to switch, become the Active server, and carry out its functions.
This Assured Recovery test is executed by starting up database services, and performing whatever operations that are required to verify the integrity of the data. All this is done without any need to perform resynchronization, and without impacting either the availability of the production server, or the safety that the Replication and HA systems are designed to provide.
During the test, the data changes that continue to take place on the Master are sent to the Replica, but they are not immediately applied. Instead, these changes are accumulated and stored in a spool, and only when the testing is completed they are applied to the Replica data. Since the spooling occurs on the Replica, if something happens to the Master during the testing process, none of the accumulated changes are lost.
Once the testing is finished, the Assured Recovery option stops the application services it started on the Replica. Then, the Replica server is automatically rewound to precisely the state that existed when the replication was paused and the test started. This way, the accumulated changes in the spool can be applied as if no testing has occurred. From this point on, the Replication or HA scenario continues normally. In the case of an HA scenario, if a failure of the Master occurred during the testing, switchover begins.
The Assured Recovery test can be fully automated and performed on a scheduled basis as often as needed. Upon completion, appropriate personnel can be alerted with the status of the test, and additional actions can be triggered on success, for example, taking a VSS snapshot of the Replica data or creating a backup. In addition, you can perform AR testing in non-scheduled mode when the need arises.
The Assured Recovery testing is tailored to all supported application and database servers. However, since the Assured Recovery option tests database services, it is less applicable for File and IIS Servers. You can still use the Assured Recovery option with these servers for special tasks. For example, you can automatically suspend replication on a regular basis during several hours each day, week or month, and run scripts in this interval, or you can use this suspension to take VSS snapshots on the Replica. Since there is no application per se, testing of the data with File and IIS Servers scenarios requires additional custom scripts.
The Assured Recovery option supports both Replication and HA solutions, except for Control Service scenarios. However, it is best suited for HA since in this case the Replica server necessarily contains the actual database servers, on which the test is performed, and not only data.
Note: The Assured Recovery option is not available for Control Service scenarios.
If you are using AR test as a part of Replication scenario, you must verify that the root directories path is the same on the Master and the Replica. In addition, the Replica should have database application installed, or share files if you test a File Server, and they need to be configured on the Master and the Replica in exactly the same way. Otherwise, the AR test will not produce meaningful results.
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