11.10.a sar

with a default Ubuntu 16.04 setup (and the LFCS VM) statistics collection is disabled and executing "sar" will result the message below. 

student@ubuntu:~$ sudo sar
Cannot open /var/log/sysstat/sa25: No such file or directory
Please check if data collecting is enabled

I would suggest  adding  a comment in the course that one  needs  to enable it first in /etc/default/sysstat like so:

ENABLED="true"