Resizing your classic database

Scale databases up or down based on your needs. You may need to increase or decrease the capacity of your DataStax Astra DB database. If a database is growing quickly or exceeding capacity, add another capacity unit (CU) to expand the storage and capabilities of the database.

This information applies to only classic databases.

You can increase your database by a maximum of three CUs. Multiple resize operations are required to add more CUs beyond the maximum number.

Consider the following conditions when resizing databases:

  • You must be the owner of a database to resize it.

  • Databases can only be increased in size to add more CUs.

  • Databases running on the Developer tier cannot be resized.

  • You cannot modify the compute size of existing databases.


  1. Open a browser, navigate to Astra DB, and log in.

  2. From the Dashboard page, select the overflow menu for the database you want to resize and select Expand CUs.

  3. In the Expand CUs window, modify the number of CUs for your database.

    The total amount of storage and estimated cost changes dynamically based on the number of CUs entered.

    You cannot increase your cluster by more than 3 CUs at a time. If you need to increase your cluster by more than 3 CUs, increase them in intervals of 3 CUs at a time until you reach the total CUs you need for your database. The maximum is 20 CUs for your database.

    You cannot decrease your cluster. If you need to decrease your cluster, contact DataStax Support.

  4. Select Expand to begin resizing the database.

  5. Confirm you want to expand your database to your specified size by selecting Yes.


You will receive a confirmation that you database is scheduled for expansion. Your database remains active while resizing, but you will have limited administrative functions. Your database status changes to Resizing until the resizing is complete.

You will receive an email when your database is successfully resized, along with a link to the database.