Cost Optimization on The David Page

When RDS Proxy Eats 70% of Your Total CloudWatch Ingestion Cost

Sun, 02 Aug 2026 09:00:00 +0700

Pulling up a client’s Cost Explorer, I found RDS Proxy responsible for 70% of their total CloudWatch Logs ingestion cost — while their actual “RDS Proxy” line item looked completely normal.

Hi everyone 👋

My first reaction, and the first reaction of nearly every client I’ve shown this number to, is always the same: “I’m already paying for RDS Proxy by the vCPU-hour — why is it also eating into my CloudWatch bill? Aren’t those two completely separate things?”

The Invisible Files on S3: Paying for Data You Can't See (Incomplete Multipart Uploads)

Sat, 01 Aug 2026 14:00:00 +0700

A large upload to S3 dies mid-transfer. The parts that already made it up don’t just vanish — they keep sitting there, billed every month, invisible to the console and to aws s3 ls.

Hi everyone 👋

When an application uploads a large file to S3 using multipart upload and the connection drops partway through, the obvious assumption is: the upload failed, nothing happened, no harm done. That assumption is wrong in a way that quietly costs money.

Archiving Millions of Small Files to Glacier: When the 'Cheap Storage' Trick Backfires

Fri, 10 Jul 2026 09:00:00 +0700

S3 Glacier Deep Archive is famous for dirt-cheap long-term storage. Point a Lifecycle Rule at millions of tiny log files, though, and “cheap” can flip into “more expensive than doing nothing at all.”

Hi everyone 👋

I once confidently set up an S3 Lifecycle Rule: “any object older than 30 days automatically transitions to Glacier Deep Archive.” Simple, standard cost-optimization advice. The catch: the bucket in question held millions of small log files, each only a few KB.

The NAT Gateway 'Trick' That Was Actually Billing You for ECR, Not S3

Thu, 18 Jun 2026 09:00:00 +0700

A client’s NAT Gateway bill hit a record ~$3,000/month. VPC Flow Logs pointed straight at S3 — except the client swore they barely used S3. Here’s what was actually going on.

Hi everyone 👋

A client came to us about a month after going live with a new system built by a different vendor — one they no longer had a maintenance contract with. Their first full invoice after launch showed a NAT Gateway bill at a record high, roughly $3,000/month. Standard architecture on their end: ECS services running in private subnets for security, NAT Gateway for outbound access. Textbook setup on paper — which made a bill that high, right out of the gate, more confusing, not less.

That CloudWatch Logs Insights Query Just Cost You $2.50

Tue, 05 May 2026 09:00:00 +0700

One click on CloudWatch Logs Insights, a few seconds waiting for results — and a bill for scanning half a terabyte of logs.

Hi everyone 👋

CloudWatch Logs Insights is a genuinely convenient SQL-like log query tool. The way AWS bills for it, though, catches a lot of people off guard.

😱 The common mistake

Open Logs Insights, pick a log group that’s accumulated 6 months of logs (~500 GB), type a broad search query with no explicit time range set, hit Run.

Cutting a Client's CloudFront Bill by ~87% with AWS's New Flat-Rate Plans

Mon, 02 Mar 2026 10:00:00 +0700

A client came to us in shock over their CloudFront bill — $1,500/month during their peak sales period. Here’s how we got it down to $200/month.

Hi everyone 👋

A client reached out to us after opening their AWS invoice during their busiest sales month of the year and seeing CloudFront alone hit ~$1,500/month, with the vast majority of that coming from data transfer out to their customers. They weren’t looking for a full re-architecture — they just wanted to know: is this normal, and can anything be done about it?

The Hidden Cost of Cross-AZ Data Transfer on AWS

Wed, 14 Jan 2026 09:00:00 +0700

Multi-AZ for high availability quietly turned into a network bill bigger than the compute bill — here’s why.

Hi everyone 👋

This is one of those “hidden landmines” on AWS: things that never throw a clear error, never show up in a StackOverflow top answer, but can quietly make a system flaky or burn thousands of dollars a month. First up: cross-AZ data transfer.

😱 The assumption that gets everyone

Everyone knows data transfer out to the internet costs money. Far fewer people realize that traffic between Availability Zones inside the same Region isn’t free either — a lot of us assume “it’s all internal, so it’s free.”