I recently installed Munin on my servers. Now 2 of my machines show big spikes in DiskIO at the same time, everyday at 4am.
I run Centos 5.6 (64bit). I've checked my cron logs, and I have no personal scripts running around those times. Also, my hoster does not take backups, as I run my own backups, but they run at 1AM, not 4AM.
My Question is: Does CentOS run any scheduled processes that can take up this much DiskIO?