In this panel we see the server details, the CPU loading and the HDD usage
The server details contains the url for the server (Hostname), the IP address of the server, the software version running on the server, the server time, how long the server has been running this software version and the connection speed to the internet.
The CPU loading is displayed for the three standard time intervals of 1 minute, 5 minutes, and 15 minutes. CPU loading is probably easiest explained by
The traffic analogy
A single-core CPU is like a single lane of traffic. Imagine you are a bridge operator … sometimes your bridge is so busy there are cars lined up to cross. You want to let folks know how traffic is moving on your bridge. A decent metric would be how many cars are waiting at a particular time. If no cars are waiting, incoming drivers know they can drive across right away. If cars are backed up, drivers know they're in for delays.
So, Bridge Operator, what numbering system are you going to use? How about:
- 0.00 means there's no traffic on the bridge at all. In fact, between 0.00 and 1.00 means there's no backup, and an arriving car will just go right on.
- 1.00 means the bridge is exactly at capacity. All is still good, but if traffic gets a little heavier, things are going to slow down.
- over 1.00 means there's backup. How much? Well, 2.00 means that there are two lanes worth of cars total – one lane's worth on the bridge, and one lane's worth waiting. 3.00 means there are three lane's worth total – one lane's worth on the bridge, and two lanes' worth waiting. Etc.
This is basically what CPU load is. “Cars” are processes using a slice of CPU time (“crossing the bridge”) or queued up to use the CPU. Unix refers to this as the run-queue length: the sum of the number of processes that are currently running plus the number that are waiting (queued) to run.
Disc usage is displayed in a Pie chart showing the amount of the HDD used and the amount of the HDD that is free.