MySQL on XFS

Thu, 11 Apr 2013 00:00:00 +0000

XFS handles database workloads better than ext4 – better concurrent I/O, more efficient metadata operations for tables-heavy schemas, and delayed allocation that improves write throughput. The obvious approach is to change MySQL’s datadir in the config. The less obvious approach is bind mounts, which keep every path where the system expects it.

Setup

Install XFS utilities alongside MySQL:

sudo apt-get install -y xfsprogs mysql-server

Create the filesystem on the dedicated volume:

Connection pooling

Fri, 20 Jul 2012 00:00:00 +0000

The mysql npm module creates one connection per client instance. Every database call opens a connection, runs the query, and you’re responsible for closing it. Under concurrent requests, connections pile up. MySQL has a max_connections setting – default 151 – and when you hit it, new queries fail.

I hit this in production. The app was handling maybe forty concurrent requests and MySQL started refusing connections. The error is Too many connections and there’s no graceful fallback. Queries fail.

Mysql on vnykmshr

MySQL on XFS

Setup

Connection pooling