Using multiple regions
You can replicate data to multiple regions for high availability scenarios to ensure active-active applications failover models. Multiple regions also ensure application data availability for locality purposes with the added value of cost savings.
Having multiple regions increase may your billing. For more, see Pricing and billing.
Video introduction
See this short video introduction to the Astra DB multi-region implementation:
Eventual consistency model and multi-region updates
DataStax Astra DB follows the eventual consistency model. Depending on the selected consistency level, data written to one region might not be immediately accessible to other regions in the same database.
If you are using the EACH_QUORUM consistency level for normal updates or SERIAL consistency level for Lightweight Transactions (LWT), then data is immediately accessible on all regions provided the operation successfully completes.
These consistency levels are for only write requests.
For all other consistency levels, data might not be immediately accessible. The time span is normally within a few minutes to fully replicate the data. However, it could take longer, and possibly span one or more days. There are several contributing factors to the latter scenario, such as the workload volume, the number of regions, the data repair operations, and network resources.
For more, see the FAQs in this topic.
Data sovereignty
Astra DB serverless replicates all data in the database to all of a database’s regions. By contrast, multiple keyspaces in Apache Cassandra® and DataStax Enterprise (DSE) allow a database to replicate some tables to a subset of regions. To achieve the same behavior as Cassandra or DSE, create a separate Astra DB instance that adheres to the necessary region restrictions. The database client will need to add a separate connection for the additional database and send queries to the appropriate connection depending on the table being queried.
Classic databases
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If you are adding multiple regions to your database, you can use each region only once. You cannot add the same region to the same database more than one time. |
Adding a region to your classic database
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Open a browser, navigate to DataStax Astra, and log in.
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On the Dashboard page, select the database name to access the Overview page for your selected database.
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Select Add Region.
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Select the region you want to add from the Add Region menu.
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Select Add.
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Confirm you want to add the region by selecting Confirm.
You’ll see a screen confirming the new datacenter region is being added. Once you add a region, a maintenance period starts that might take up to 30 minutes. Your database will have limited availability during this window. Some actions, such as viewing database connection details, might be unavailable until maintenance is finished.
Removing a region from your database
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Open a browser, navigate to DataStax Astra, and log in.
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On the Dashboard page, select the database name to access the Overview page for your selected database.
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Select Remove Region from the overflow menu for the region you want to remove.
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Enter your datacenter id, which is provided in the prompt.
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Select Remove region.
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Removing a region is not reversible. Proceed with caution. |
You’ll see a screen confirming the datacenter location will be removed. Once you remove a location, a maintenance period starts that might take up to 30 minutes. Your database will have limited availability during this window. Some actions, such as viewing database connection details, might be unavailable until maintenance is finished.
What’s next?
See additional database management topics.