Astaro Security Gateway has included atop since v7.400.
Homepage atop: http://www.atoptool.nl/
Known to apply to the following Sophos product(s) and version(s)
Astaro Security Gateway / Sophos UTM
V7, V8, V9
What To Do
To write atop logfile
nohup atop -w /var/storage/atop.log 60 & atop is now running until you reboot or kill it with: