Posted on MySQL Ninjas | August 2026
Every DBA has been there. An alert fires. You SSH into the box,
run free -h, and see MySQL consuming far more RAM
than you configured. You double-check
innodb_buffer_pool_size. It's set correctly. So
where is the memory going?
This is the story of debugging exactly that — on a Google Cloud
c4d-standard-4 instance with 14.7 GB RAM, MySQL
configured with a 7168 MB buffer pool, and mysqld RSS sitting at
10.4 GB. That's a 3.2 GB gap nobody could
explain.
The Setup
We run a large …
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