Centos – High CPU load on Centos with process sync_supers

In top, press "1". You may find a single processor is overloaded.

Normally, I see this sort of thing with iowait, but yours is at zero. Still,

iotop 

may be informative.

This is when the cron.daily scripts run... By default, it runs daily just after 4:00am.

From /etc/crontabs

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily <-- THIS ONE!!
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly

And in /etc/cron.daily.

The culprit is probably your mlocate.cron, which runs updatedb and can be quite intensive on some systems:

#!/bin/sh
nodevs=$(< /proc/filesystems awk '$1 == "nodev" { print $2 }')
renice +19 -p $$ >/dev/null 2>&1
/usr/bin/updatedb -f "$nodevs"