How do I know when StoreForward data is securely stored in Historian?

Question

In a meeting with a customer, who have had challenges on their network that triggered StoreForward on one or more AppEngines I received a collection of questions related to how it works, how to visualize status for the operator and whether it is 100% bulletproof. 
 Objectviewer lists these attributes related to StoreForward: 
 
 Historian.InStoreForward 
 Historian.InStoreForwardMask 
 Historian.StoreForwardDataLost 
 Historian.StoreForwardDeletionThreshold 
 Historian.StoreForwardMinDuration 
 Historian.StoreForwardProblem 
 Historian.StoreForwardSpaceAvailable 
 
 DeletionThreshold and MinDuration is part of the configuration, but where to find the details on the rest? 
 I guess they can be used to inform the operator &ndash; but details are needed to ensure that we are not misleading the operators. 
 In my test environment I can see that InStoreForward toogles if I stop and start the Historian, but does the value &lsquo;false&rsquo; mean that the Historian is back online AND data is forwarded to the Historian? 
 Or how should I verify the transfer is completed? 
 Will Historian acknowledge the transfer of data when they are in the RAM of the Server? - or will it happen when data is merged into the HistoryBlocks.

Hardik Shah · Answer

Michael Vittrup 
 When the Historian becomes available again, the App Engine immediately sends all data from the Store-and-Forward folder to the Historian. The time required for this transfer depends on the size of the stored data. You can verify this by checking the Store-and-Forward folder after the Historian is available: if there are no .dat files present, it means all data has been successfully transferred to the Historian.