I tried sleeping 0.1s every 5s or so. It did not help. Still crashed. I don't think swapping would even occur since neither mysql nor php grow their memory usa

I tried sleeping 0.1s every 5s or so. It did not help. Still crashed. I don't think swapping would even occur since neither mysql nor php grow their memory usage over time. It's not an SSD. It's good old rusty HD.