The major difference between V1 and V2 is that V1 can scale down to 0 active nodes and only spin up a node when needed. This process is not instant, there is a bit of a delay. V2 doesn't do this, but it also means that V2 has no "idle" mode so you are paying at least something 24x7.

Thank you for your questions regarding the migration from Aurora Serverless v1 to v2. I'll address each of your concerns based on the available information: 1. Timing and Maintenance Window: AWS has announced the end-of-life date for Aurora Serverless v1 as March 31, 2025. It's strongly recommended to upgrade any Aurora Serverless v1 DB clusters to Aurora Serverless v2 before that date. The upgrade process may involve a change in the major version number of the database engine. While AWS will likely try to perform the upgrade during your defined maintenance window, it's important to note that starting January 8, 2025, customers will no longer be able to create new Aurora Serverless v1 clusters or instances. It's unclear whether AWS will provide specific notifications for individual upgrades, so it's advisable to proactively plan and implement the switchover well before the end-of-life date. 2. Impact and Downtime: The migration process from Aurora Serverless v1 to v2 can be designed to minimize downtime. However, some downtime is likely unavoidable during the final switchover. The exact duration can vary depending on your specific setup and the migration strategy used. A recommended approach involves creating a blue/green deployment, which allows for upgrading the engine version without affecting the original cluster. This method can significantly reduce downtime compared to directly converting the original cluster. 3. Identifiers and Configuration: Regarding ARNs, hostnames, usernames, and passwords, it's best to assume that some changes may be necessary. While the goal is typically to maintain continuity, it's crucial to review and test these elements as part of your migration plan. For AWS CDK scripts, pay close attention to any references to Aurora Serverless v1 specific configurations or features that might not be directly compatible with v2. 4. Snapshots and Engine Version: It's a standard practice for AWS to create automatic snapshots before major changes, but it's always a good idea to create your own snapshot as an additional precaution. Regarding your PostgreSQL version (13.12), while efforts are made to maintain version compatibility, it's important to verify the supported versions for Aurora Serverless v2 in your region. You may need to upgrade to a more recent version that supports both Aurora Serverless v2 and the features you require. Given the complexity of this migration and its potential impact on your systems, it's highly recommended to plan and execute the upgrade well before the end-of-life date. This allows time for thorough testing and addressing any unforeseen issues. Consider creating a detailed migration plan, including a testing phase in a non-production environment, to ensure a smooth transition to Aurora Serverless v2. **Sources** Migrating to Aurora Serverless v2 - Amazon Aurora Aurora Serverless v1 and Aurora database engine versions - Amazon Aurora Migrate Aurora Serverless v1 cluster to v2 | AWS re:Post Aurora Serverless v1 - Amazon Aurora