I have noticed decrease in server performance (page load speed become lower), then I went to investigate and have found in munin graphs (which tracks server's resources) that there was big changes on disk IOPS, disk latency, MySQL queries quantity. It was happened without any changes by myself to system or to programs/websites code that runs on server.
What does it mean? What trigger these changes? How to fix?
More info about issue: Order is by munin graphs sequence. Resource (approx. change in times to previous monitoring);
- Disk IOs per device (increased x10);
- Average request size (decreased x2-4);
- Disk latency per device (avg. write IO wait time decreased x10);
- MySQL queries (decreased x2);
- CPU usage (increased x1.5);
- Interrupts and context switches (increased x10).
Thank you in advance for solving this out.