Alibaba Cloud Full Stack (5): RDS and PolarDB — The Database Layer

Sat, 02 May 2026 09:00:00 +0000

My self-managed MySQL on ECS lasted exactly four months before a disk I/O spike during peak traffic brought the whole thing down. The InnoDB buffer pool was fighting the OS page cache for memory, the binary log was filling the system disk faster than my cron job could rotate it, and the single-threaded replication to my “backup” instance was nine hours behind. I fixed it at 3 AM by throwing more disk at it. Then it happened again two weeks later. That is the day I learned why managed databases exist — not because I cannot run MySQL, but because I do not want to be the person paged at 3 AM when MySQL decides the relay log is corrupted and the only fix is to rebuild the replica from a cold backup that may or may not be consistent.

Terraform for AI Agents (5): Storage — Vector, Relational, and Object Memory

Fri, 20 Mar 2026 09:00:00 +0000

Most tutorials gloss over an agent’s memory. ‘Just put the embeddings in Pinecone, the sessions in Postgres, and the screenshots in S3.’ On Aliyun, all three are managed services. Correctly provisioning them with Terraform can mean the difference between a working memory and losing three weeks of conversation history because the disk filled up at 4 AM.

This article covers all three layers, their Terraform configurations, the critical but tedious backup and disaster recovery (DR) setup, the major version upgrade process, and the Saturday outage that changed how I do things.

RDS on Chen Kai Blog

Alibaba Cloud Full Stack (5): RDS and PolarDB — The Database Layer

Terraform for AI Agents (5): Storage — Vector, Relational, and Object Memory