Instantly save 10% on your RDS bill
AWS’ proprietary ARM-based Graviton chips have existed for many years now, but there are still a surprising number of engineering teams out there who aren’t yet leveraging them. If you aren’t sure whether you’re using Graviton, you can quickly check by looking at your EC2 and RDS instance types—anything with a “g” in the name (like
m6g) is running on Graviton.
Fortunately, Graviton CPUs aren’t only available for your EC2 compute. You can also use them to power your RDS instances—and that’s almost always as simple as changing a value in Terraform.
The main thing that would block a swap over to ARM are user-defined functions written in C. If you’re using RDS you don’t need to worry about these, however. Loading a compiled UDF requires you to both move the binary into the filesystem of your database server, and have superuser permissions to actually load the binary. You can do neither of these things with an RDS instance, which makes swapping from a
db.t3 instance to a
db.t4g instance safe in almost all circumstances.
db.t3.xlarge with instance running postgres with one standby costs US$0.896/hr in
ap-southeast-2 region compared to only US$0.813/hr for a
db.t4g.xlarge. This is a 9.7% saving, and given that database spend is often one of the most expensive line items on an AWS bill that cost reduction can go a long way.
If you aren’t using Graviton-based RDS instances, I recommend you give them a try in your staging environment. In Terraform it’s a one line change, and in ClickOps all you need to do is change the value of your instance class dropdown. There are few ways to save so much on your AWS bill with so little effort.
A note on regional pricing
As an aside, RDS pricing varies massively between regions. That same
db.t4g.xlarge configuration costs only US$0.517/hr in
us-east-2, which is a 36.5% saving. Almost all AWS products have different price points by region, but for RDS the difference can be huge.
While you should primarily be choosing your region based on its proximity to your customers, it’s worth checking out price differences before commiting.
us-west-2 are both located on the west coast, for instance, but
us-west-2 has 24.4% cheaper RDS instances. Unless your use case is extremely latency-sensitive, it makes a lot of financial sense to deploy to
us-west-2 instead of