16.04 Xenial
APT automatic update check: enabled
APT automatic update download & install: disabled
No cron jobs listed below,
$ for user in $(cut -f1 -d: /etc/passwd); do sudo crontab -u $user -l; done
The system suddenly top
ped by heavy load pertaining to both CPU and Network IO from the aroused unattended-upgrade
for several minutes.
Why could it happen when automatic update download & install were totally disabled?