Server tuning

A WordPress performance audit checklist Performance work on WordPress sites often starts with a caching plugin and a vague feeling, and ends without knowing what helped. An audit turns it around: measure first, go through the layers from the server to the browser, write down what is wrong, and fix the biggest problem first. This…

Optimize WordPress database tables: cleanup, ANALYZE and OPTIMIZE Over the years a WordPress database collects revisions, expired transients, trashed posts and orphaned meta rows, and the large tables (wp_posts, wp_postmeta, wp_options) get fragmented. The MySQL optimizer also works with index statistics that can be outdated after big imports or deletions. Three commands help: ANALYZE TABLE…

Lower WordPress TTFB with Redis as a persistent object cache WordPress caches options, posts, terms and user data in memory, but only for one request. The next request asks MySQL again. A persistent object cache keeps these values in Redis between requests, so a page that needed 80 queries needs 10. It helps where a…

MySQL primary-replica replication with GTID for WordPress When one database server cannot keep up with the reads of a busy WordPress site, a replica takes part of the load: it receives every change from the primary and can answer SELECT queries. With GTID (global transaction identifiers) the replica tracks its position by transaction, not by…

Tune the PHP-FPM pool for WordPress PHP-FPM runs a pool of PHP worker processes; each worker handles one request at a time. Too few workers, and requests wait in a queue even though the CPU is idle. Too many, and the server runs out of memory and starts swapping, which is worse. The right number…

Enable the MySQL slow query log and analyze WordPress database performance Without logging, slow queries are invisible: the site is slow, but it is not clear which query, from which plugin, is to blame. MySQL’s slow query log records every statement that runs longer than a threshold. It can be enabled on a live server…

Set up Nginx FastCGI page caching for WordPress so anonymous page views are served directly from disk without hitting PHP-FPM or MySQL, dramatically reducing server load.

Use htop, vmstat, and iostat to identify CPU, RAM, and disk I/O bottlenecks on a WordPress VPS before they cause downtime or slow page loads.

Use jpegoptim, optipng, pngquant and cwebp to bulk-compress WordPress uploads on a Linux VPS and automate optimisation with cron.