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If you have started using it, you may have found that backing up Azure Cosmos DB is pretty limited by default. Having recently deleted a test database by mistake and waited three days to get round the support maze to have it restored, it was a good chance to implement a more robust backup strategy.
The simplest way I have found to do this is to backup the entire DB using Azure Data Factory. Naturally it may depend on your DB size and you may want to instead backup the change feed on a more regular basis, but this worked for well for me in the scenario I encountered.
Steps to Backing Up Azure Cosmos DB
To get started with Azure Data Factory:
- Add it as a service through the Azure Portal
- Click on Author and Monitor to be taken to the homepage
- Click on Copy Data
- Fill out the name for your task
- Add a Cosmos DB Linked Service as a source
- Fill out the connection details
- Select the Cosmos collection (Items in the case below)
- Select “Export as-is to JSON files”
- Create a Destination Source
- Use a new Azure Blob Storage linked service
- Define the file path and name, using a temporary name for now
- Click several Nexts until the wizard completes and creates the Pipeline
- Click on the pencil icon an navigate through the Pipelines to find your newly created Copy Data Pipeline
- Click on the Copy Data activity and navigate to the Sink section
- Edit the Sink Dataset
- Find the filepath, select backup.json and select Add Dynamic Content
- Change the value to “@concat(utcnow(),’.json’)” so that each run will give the file a unique name
This completes it all so that you can now Debug to test it and then Publish when all ready. Depending on your preferences, you can create a Trigger to run this every day or to whatever frequency you need. To restore these backups, create a similar Copy Data task going back the other way.
Backing up Azure Cosmos DB in this way provides some reassurance that should you accidentally delete in the portal it can be easily recovered.
By Kevin McDonnell, Senior Technical Architect at Ballard Chalmers
About the author
Kevin McDonnell is a respected Senior Technical Architect at Ballard Chalmers. With a Master of Engineering (MEng), Engineering Science degree from the University of Oxford he specialises in .NET & Azure development and has a broad understanding of the wider Microsoft stack. He listens to what clients are looking to achieve and helps identify the best platform and solution to deliver on that. Kevin regularly blogs on Digital Workplace topics and is a regular contributor to the monthly #CollabTalk discussions on Twitter.
