Monitoring & metrics

# Experience website speed yourself

Your website is slow? Feel it! Common signs of performance issues are:

• Pages are slow to load - the browser loading icon spins
• You see timeout errors - a 504 error printed on screen

# Check the browser dev tools

Open the dev tools of your browser and use the performance related tools provided to measure and identify the source of the problems. The network tab is a good starting point. You can do a performance test like Lighthouse too. The dev tools can help to distinguish between frontend and backend related performance issues.

# Check the hosting metrics

The fortrabbit dashboard offers a metric section (your hosting provider likely will have something similar) including the following vital data points:

• PHP response time: Aim for less than 250ms on average. In our experience, it's more likely that a website with an average high response time will have problems. Slow websites that are getting some more visits than usual are tending to break down (504) faster.
• 5xx error metric: See if there are any peaks in 5xx errors. If there are, see if at the same time, the PHP response time went up, in that case those 5xx errors are likely 504 time out errors.
• Memory usage: The memory used should not come to close to the hosting resources you have booked on average, 80% average usage and single peaks are Ok.
• Memory swap usage: Swap is when there is no (fast) RAM available anymore and data needs to be accessed from disc (slow). This should be within bounds, which depends on your website.
• OpCache: This should usually not max out. Aim for 80% or less. Higher values are usually not a problem.