Apache Status Scoreboard Explained
Apache Web Server’s status page and command line status show something called a scoreboard. The scoreboard is a quick way to see what apache web server has been up to in the last little while. This is a great visualization tool to debug performance and uptime issues. Let’s pull apart the scoreboard and explain what’s going on.
Prerequisites
In this article, we assume you know how to access your web server status and have seen the scoreboard feature. If you aren’t sure how to see your apache status, you might find one of these guides helpful:
Scoreboard Example
Here’s a few examples of what your scoreboard might look like.
So what do all those dots mean? What does the W mean? Let’s dig in!
Symbols On the Scoreboard Explained
Here are some of the symbols you may see on your scoreboard and what they mean:
- “_”: means waiting for a connection
- S: Apache is starting up
- R: Apache is reading a request
- W: Apache is sending a reply
- K: A client request is idle, but apache is keeping the connection active (keep alive)
- D: Apache is doing a DNS lookup
- C: Apache is closing a connection
- L: Apache is writing something to a log file
- I: Apache is terminating an idle worker
- “.”: Apache is idle
Diagnosing Issues with Apache Status Scoreboard
We can use the apache scoreboard to diagnose what’s going wrong with our web service. Here are a few common situations to look for.
Performance Issues
When you have performance issues, your apache scoreboard will give you indicators that it’s not able to keep up. You’ll notice there’s a lot of W characters and very few (if any) _ characters. This means all the workers are active and they’re spending their time writing to the response stream. This typically means your backend or filesystem isn’t able to keep up with the requests coming in.
If you’re having this sort of trouble, check that your web server has enough RAM and CPU to handle the current load. You may also need to implement caching or refactor some of your slower
DDOS Attack
During a DDOS attack you may see a lot of R characters. This is because the attacker is opening a lot of connections, but not writing anything to them. Apache is stuck in a read state, waiting for the client to send data.
In a situation like this, you often need to implement a web application firewall to protect you. You can also block individual IP addresses if the attack is localized.
Putting it all together
Apache’s scoreboard is a great tool to help you see what’s going on at a glance. You can use it to diagnose performance issues and DDOS attacks. If you would like to read more about apache’s status and uptime, check out our Ultimate Apache Web Server Guide.