Downsizing resources on rds Database

Question

I downsize a production database ( RDS PostgreSQL) from 16 GB ram to a 8 GB ram and at first I had 11 GB free memory and now I have 5 GB of free memory , from that logic I can still downsize to a 4GB ram without any problem correct ? By the way my CPU utilization and the rest are prety low.

Accepted Answer

Hi,

To start with, you can upscale or downscale instance class based on CPU/RAM/IO requirement for your application. So if you think, 4 GB RAM and 2 vCPU is enough for your application workload, then you should downscale instance class to appropriate instance class for example: db.t4g.medium which has 2 vCPU and 4 GB RAM [1].

Furthermore, always remember to check supported instance class for DB engines [2].

Hope it helps and if it does, I would appreciate if answer can be accepted so that community can benefit for clarity when searching for similar enquiries in repost/aws guide.

**References**

[1] https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.DBInstanceClass.html#Concepts.DBInstanceClass.Summary : DB instance classes - Hardware specifications for DB instance classes

[2] https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.DBInstanceClass.html#gen-purpose-inst-classes : DB instance classes - Supported DB engines for general-purpose instance classes

Answer

Hi,

Did you think about using Aurora Serverless for pg since your utilization is low: https://aws.amazon.com/rds/aurora/serverless/

You would solve 2 issues in 1 shot:
* the RAM tuning that you need to do will be done by Aurora
* Aurora is pay-as-you-go: costs are very low for a very low utilization

Best,

Didier

Downsizing resources on rds Database

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