What you can do is to monitor the droplet’s performance and see if there are any spikes in the CPU and memory usage. This will help you to determinate if the issue is related with the lack of server’s resources when your site is busy handling requests.
The thing is the issue might not be related with your website itself and you might experiencing the speed issues because your server is running low on memory. That is why it’s important to make sure that everything is operating normally.
You can also examine the logs for any killed processes as this will help you to see if the server is killing processes in order to remain stable. You can check this by looking at the /var/log/messages and search for kill, e.g
grep -i kill /var/log/messages
You can also check for
out of memory (The OOM Killer) references in the log to see if the system is critically low on memory. This usually indicates that you need to upgrade if there are a lot of references.
grep -i oom /var/log/messages
You can exacute
htop via ssh to see what process is taking the most CPU or memory. Both tools are really handy when it comes to monitor the server’s performance. I would like to mention that
top comes installed by default and you might need to install htop.
sudo apt-get install htop
yum install htop
Top provides a simple, real-time table of your processes, with the largest consumers on top. Running htop, we can see that it has a similar output, but is colorized, and is more interactive:
There is a really useful tutorial you can check on how to use top, htop, netstat, du and other tools to Monitor Server Resources:
You can also use sar to check what’s going on your droplet. With sar, you can monitor performance of various Linux subsystems (CPU, Memory, I/O..) in real time.
You can use it like this:
To check the memory usage (Free and Used ):
To check the cpu usage:
You can also check this tutorial for monitoring the CPU usage on your droplet:
You can also track the performance with the Droplet Graphs which are available in your control panel. You can find more information here:
Hope this helps!