Our site goes down because the IO on our database servers is too slow.
Troubleshooting this we found that mysql is really really slow. It's constantly reading from disk and I think not using enough memory. It's using about 30G when it usually uses about 100G.
Here is the
What can I check to see what is causing massive IO reads from mysql?
How can I find out why mysql is so slow and using so much disk IO?
This is the current iostat https://gist.github.com/simao/3657e6ac9fab0376acc0
But we are up at the moment and when we are down IO is 100% and disk reads are really slow.
We are using InnoDB with SSD storage on a dedicated machine.