Quick summary. Wordpress community website, large userbase. Has caching for guests (WP Super Cache). Always operates around load of 1-2, or 5-6 at peak hours CPU.

As of 4pm EST on Feb 15, the CPU load shot to 10 and ever since then has had a "resting" load of 7-8 and is at extreme levels during the day usually 12.

What was tried:

  • Many reboots, it goes right back up to 12.
  • Blanked out the website for users, guests were served cache. Load stayed at 8 (weird?...)
  • Slow query log is useless, logging many non-normally-slow queries because entire server is slow.

Here is a typical htop snapshot: https://i.stack.imgur.com/2o3II.png

The moment it happened: https://i.stack.imgur.com/QXdpV.png

No plugin/code changes...Why?

I sort of feel it's not just slow plugins/frontend queries and such, due to how it immediately jumps to 12 on reboot and how even with the site blanked out (not calling up posts, comments, sidebars, etc) it was still at a very high load.

How can I determine what's going on?

  • Most WP load problems are helped by WP Index Improvements
    – Rick James
    Mar 1 at 0:22
  • Perhaps the "Super Cache" is adding to the load more than it is helping? See what happens when you disable it.
    – Rick James
    Mar 1 at 0:23
  • Even a load average of 4 is "high", in my opinion.
    – Rick James
    Mar 1 at 0:29
  • Also strange: Why is all the CPU usage in a single core?
    – Rick James
    Mar 1 at 0:46
  • thanks - disabling cache just cripples the site harder, it does seem to work and visiting the site as guest is somewhat speedy ... also about CPU, it seems like its spread across all 4 no? all cores are at 100% @RickJames Mar 2 at 1:14


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