Trying to fix the ‘Varnish cache 404′ error? We can help you in fixing it.

The Varnish cache 404 means that the file is not found and it indicates that the data is not updated in a timely manner.

At Bobcares, we often receive requests to fix the Varnish cache error as a part of our Server Management Services.

Today, let’s see how our Support Engineers fix the varnish cache error.

Explore more about Varnish Cache Error

Customers often approach us with Varnish Cache errors. The 404 status code indicates that ‘File Not Found’ error.

Varnish cache increases the speed of a Website but takes up space on the device such as a computer, smartphone or tablet.

By default, along with other cached contents, the Varnish Cache holds onto 404 responses. The following status codes are cache by default in Varnish Cache.

• 200: OK
• 203: Non-Authoritative Information
• 300: Multiple Choices
• 301: Moved Permanently
• 302: Moved Temporarily
• 304: Not modified
• 307: Temporary Redirect
• 410: Gone
• 404: Not Found

The 404 error occurs if we don’t update proper data in a timely manner or due to any other mistakes.

How to fix Varnish 404 Error?

Recently one of our customers approached us with the varnish cache error. Let’s discuss how our Support Engineers resolve the error for our customers.

We fix the 404 error by changing the settings in the vcl_backend_response section. By doing this it prevents the 404 responses being cached at all. So that they are only cached for a short period of time.

We make sure that Varnish Cache does not Cache a 404 Error by adding a code to the vcl. In the vcl_backend_response section, we add the below code.

sub vcl_backend_response {
# Don't cache 404 responses
if ( beresp.status == 404 ) {
set beresp.ttl = 100s;
set beresp.uncacheable = true;
return (deliver);
}
}

If we do not want to cache 404 error codes at all then we change 100s to 0s in the above code.

Also, by putting this code in the vcl_backend_response section, the Varnish Cache does not cache any backend response with a 404 status. Because of this code, the requests for the next 100s get sent straight to the backend.

We prefer to cache them for a short period of time so that it protects the backend from the load. Here is the code for the shorter period of time.

sub vcl_backend_response {
# Don't cache 404 responses
if ( beresp.status == 404 ) {
set beresp.ttl = 30s;
}
}

Finally, this fixed the error.

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Conclusion

In short, the Varnish cache 404 error indicates Not found status code. Today, we’ve discussed how our Support Engineers fix the error by modifying the Varnish response code.