Ok, so I have a fast dedicated server with 32GB Ram, 6 Cores, 15mb cache, 2x1 TB Harddrives, with RAID-1. Everything has been optimized and Nginx settings perfected. We have about 240 sites.
Here is the problem-
The sites are fast, but then...
When we are working on them they start slowing down, after a few hours it goes from 1.5 sec load time to about 15 seconds. If there are multiple people working then that time goes from 1.5 sec to about 30 sec within an hour or so.
When we are not working on them it takes about 24 hours to go from 1.5 sec to about 20 sec load time.
Found a temporary solution, but I need a permanent one.
The temp solution is:
I deactivate ALL plugins and then activate ALL plugins. It seems to reset something and it is fast again. Literally, like nothing is wrong.
When I look at NewRelic everything looks good except it says that about 95% of the load is in admin-ajax.
So my question is what is the long term solution? Why is it when I deactivate them all and then activate them all it gets back to being fast? Any help is very much appreciated! Thank you!