====== vmstat ======
<code bash>
# update every second, size in mb
vmstat 1 -S m   
</code>

====== iostat ======
<code bash>
# update every 5 seconds, extended, size in mb
iostat -t 5 -x  -m
</code>

====== sysstat ======
Sysstat is a daemon that collects statistics in a regular interval. 

===== installing =====

Before it can be used it needs to be installed installed with

<code bash>
sudo apt-get install sysstat
sudo vi /etc/default/sysstat   # set ENABLED="true"
</code>

the stats collection is triggered every 10 minutes by cron (/etc/cron.d/sysstat)

===== using =====
Once stats have been collected, they can be viewed using the **sar** command

<code bash>
# show cpu usage
sar

# show memory usage
sar -r

# show disk usage
sar -dp
</code>