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Error: Unable to download blob

Article # 3048388 - Page views: 49


"Unable to download blob" error occurs potentially in different places in a TotalAgility Cloud system or in a non-cloud system configured to use Azure blob storage.



Azure blobs referenced in the KTA databases do not exist in Azure blob storage



KTA databases and Azure blob storage must be in a synchronized state.  So for example if KTA databases are restored to a previous point in time, then Azure blobs must be restored to the same point in time. 

Another situation is if Azure blobs have been deleted for any reason outside of KTA.  For example if setting retention policy settings in Azure, old blobs can be deleted even if KTA is still using them.  One misconception that can lead to mistakes is thinking that Azure blobs are only used for document data.  Thus it seems logical that if a system never expects to keep documents longer than a certain time, then it would be ok to enable retention settings in Azure blob storage.  However, Azure blob storage is also used to store “customer assets” (referenced in KTA’s CUSTOMER_ASSETS table), such as form images, css files, .NET dlls, and other data.  There are also folders and documents that persist longer than might be expected, due to how Online Learning store data.  The only safe approach is to allow KTA to manage deletion of blobs.

If Azure blobs are not recoverable then the data in KTA is not recoverable either.


Level of Complexity 



Applies to  

Product Version Build Environment Hardware
KTA All      


Article # 3048388
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