A few days ago i moved my website from a shared host to VPS, The site was loading fine without any issues at shared hosting but surprisingly, after moving to new powerful VPS server, i noticed my site and others were actually slowing down.
I tried everything, disabled several plugins, installed nginx and CDN to speed up site but failed so i contacted my host. They investigated it in detail and here is what they told me!
I was watching your system for the past few hours and was tracing processes running there and, at this point, I don't think w3tc plugin is good for you and instead of improving the site speed it actually slows it down. While tracing php processes I noticed that on each site request this plugin reads every single file under the /home/username/public_html/wp-content/w3tc/ directory. At this very moment there are 4769 files and 12797 (!) directories under the /home/username/public_html/wp-content/w3tc/ directory. Based on what I'm seeing so far scan through these ~20k objects is what takes majority of time.
Could you please try to disable the w3tc plugin to see how things will run? Please let me know.
Weird, So i went ahead and disabled the plugin and site is loading fine now!!
Can developer of this plugin please help and look into this?