Long Loads & Erratic TTFB

[dfavor]

Number of resource to load effects total load time.

TTFB relates primarily to your hosting, so LAMP (Linux/Apache/MariaDB/PHP) tuning.

You're running WordPress, so you can try this.

1) Install Query Monitor plugin

2) Set SAVEQUERIES to true in your wp-config.php

Look for huge numbers of broken HTTP requests or database thrash.

Recently I found an odd glitch between how WordPress calls it's own API on WP.org which related to DNS... where... some DNS lookups simply failed, after a 5 second timeout.

After narrowing this down to DNS, I've changed all my LXD containers to...

a) Remove the massively broken systemd-resolved nonsense.

b) Change /etc/resolv.conf to "nameserver 127.0.0.1"

c) Run - resolvconf --disable-updates - each time containers reboots, so /etc/resolv.conf never changes.

d) Arrange for dnsmasq (blazing fast DNS resolution) to listen on 127.0.0.[1|53] to handle all DNS.

This has resolved many complaints I was having from clients about slow sites, especially when logged into the admin dashboard.

Query Monitor can surface many problem areas.

Also make sure Opcache is enabled + tuned well. http://167.114.29.137/wptools/ocp.php shows what you're looking for. Lots of free memory slabs + keys.

Also run mysqltuner on a regular basis + fix any emitted diagnostics.

Few weeks ago, I went through a tuning cycle with latest mysqltuner + latest MariaDB on a high traffic site + got nearly 60% disk i/o reduction by fixing every single mysqltuner suggestion.