You might be wondering why your AWS expenses for RDS shoot up in the last few months or maybe you already know this is caused by the Amazon RDS Extended Support for Aurora and want to migrate your engine version, if so this post is for you.

Late in 2023, AWS informed Aurora users to migrate the version of the Aurora engines due to the deprecation of the MySQL Community major version 5.7 and it was recommended to migrate to major version 8.0.

[!cite] AWS Announcement: https://repost.aws/articles/ARHdQg4IelQS2uyXkNrINw-A/announcement-amazon-rds-extended-support-opt-in-behavior-is-changing-upgrade-your-amazon-rds-for-mysql-5-7-database-instances-before-february-29-2024-to-avoid-potential-increase-in-charges

As part of the AWS strategy to force you to migrate to a new version, if you meet the EOL support deadline, you will be automatically enrolled in the Amazon RDS Extended Support program in which you technically get access to:

  • Security updates for critical and high CVEs- for your DB instance or DB cluster, including the database engine.

  • Bug fixes and patches for critical issues.

  • The ability to open support cases and receive troubleshooting help within the standard Amazon RDS service level agreement.

This sound like a cool upgrade but it comes at the cost of 0.1$ per V-CPU/HOUR for the 1st and 2nd year, the 3rd year it will increase to 0.2$, this also sounds cheap but when you make the calculation you will quickly find out that your Aurora expenses will increase by a 2 or 3 times.

AWS RDS Extended Support Cost Imag

The first time I had to migrate the engines, I was asked to measure how much this will impact our costs as this doesn’t look like too much - $0.1 per VCPU - and as soon as the numbers were on the table, migrating became high priority. The following table will show you the additional costs we would’ve have to pay every month:

Instance Type Instances V-CPUs Additional Cost Monthly 1st & 2nd Year Additional Cost Monthly 3rd Year
db.r5.4xlarge 2 32 (16x2) $2.380 ($0.1 x 32VCPU x 744H) $4.761,6 ($0.2 x 32VCPU x 744H)
db.t3.small 12 24 (2x12) $1.785,6 ($0.1 x 24VCPU x 744H) $3.571,2 ($0.2 x 24VCPU x 744H)
Total 56 $4.165,6$ $8.332,8

This was 2 and 3 times the monthly budget for databases at that time, and this was enough to start migrating databases to the new engine.

Even though the RDS Extended Support was informed a few years ago, there are still accounts not migrated, In the following images, we can see how the costs of the following customer increased by 4x.

Costs before AWS Extended support:

Costs without AWS Extended support

Costs with Extended Support: Costs After AWS Extended Support:

Almost 300$ extra billed each month:

RDS Billing Detailed

The references in this post were for small and medium size business but these unexpected cost that can impact dramatically the expenses of any project at any scale.

Important before migrating⌗

  • Create a to do list with all the steps needed to accomplish the task, this way the production databases migration will be seamlessly.
  • Migrate lower environments first (DEV, QA, STAGGING, RELEASE,, PRE-PROD, …).
  • Pay attention to Paramenter Groups and Option Groups, you will have to create new ones and the old ones will be useless after migrating, the configuration is not migrated automatically.
  • MySQL 8.0 will only run on Medium size instaces at minimum, having Small instances means upgrading to Medium size first.