Although CDN network is already an advanced solution, you can improve it by tailoring to your needs and business. A perfect content delivery network means excellent web performance, so this time we will learn to understand it better.
As a rule, CDN providers rarely mention the impact of their service on business’s bottom line. Advertisements say “We will make your website faster!”, but CDN benefits extend beyond the limits of site speed – there’s also such a great merit as bandwidth saving. Since CDN companies usually charge customers depending on bandwidth usage, they offer various methods for using less bandwidth – you should use them to optimize your content delivery strategy. Besides, you should be aware of both when your CDN is functioning (has a high cache hit percentage, for example), and how it’s functioning. This way, you’ll be able to troubleshoot CDN configuration and adjust it properly.
With these ten tips and CDN practices, you will evaluate, optimize and analyze work of your content delivery network. Repeat these steps from time to time to reach excellence.
1. The Rule of 20 Days
According to recent researches, CDN starts impacting traffic and search engine rankings within 20 days after implementation. Although website page loading speed improves in a split second, other variables, such as Google rankings and unique page views are impacted with the time being. If your content delivery network has been properly set up and is simply suitable for your project, you may experience more than 400% spike in click through, and 1000% + spike in traffic after 20 days (these results vary). The delay may be caused by the time it takes Google to recrawl a faster, CDN-charged website.
If you run an online business, more traffic means higher conversions and better finances (40-50-60% and more). Just be patient after you leverage a CDN and see how traffic changes then.
2. Measure the Influence of Your CDN
You should measure conversions and load times before and after CDN use to know exactly which impact it makes. This simple test will allow you to:
- Define whether CDN expenses are worth performance (page load times) it maintains;
- Understand the influence of CDN on your bottom line (conversions);
- Make future research of CDN on conversions.
Please note that this simple test does not show how CDN handles traffic spikes and guarantees uptime. If you want to check CDN’s reliability, you can resolve to such tools as Load Impact, Loadster, or Neustar.
3. Create a Failover Strategy
Now there’s need to ensure ultimate uptime with the help of a CDN failover strategy. Downtime can cost you even more than you can imagine: a few seconds of downtime deprived Amazon of several million dollars! Therefore, backup service is of utmost importance – although CDN is generally a failure-proof system, outages still occur. Before trying some certain option, as yourself a few questions:
- Define whether success of your website depends on a never-failing CDN.
- Determine whether it should be a passive, or an active failover strategy.
4. Use Open Source CDNs
5. Optimize Images
This is the next step that should be taken even before you implement your CDN – image optimization helps to save bandwidth and boost loading time considerably. Pages with images can weigh about 2.1 Mb (which is twice more than in 2011), and images averagely compose about 62%. They not only make page loading slower, but also hog CDN bandwidth.
Just consider that: if you have a 500 Kb image that can be optimized to 50 Kb, you can serve one person at the cost of ten – that may help you to save of bandwidth considerably. In order to avoid bandwidth overage and optimize loading speed, run your images through ImageOptim, or implement plugins (especially convenient for WordPress websites). There’s an abundance of free tools for image optimizations in the Net – be up for grabs.
6. Reconfigure Your CDN After Origin Alteration
In order to prevent redirects, you need to change CDN configuration after SSL enabling, addition of query strings or any other changes to your origin. If you don’t make corresponding changes to your CDN, it may result into redirects to the origin for fetching cacheable assents, which means more cache misses and longer loading time for visitors. Redirect increases the number of required actions and loading time subsequently.
7. Encrypt CDN Assets for HTTP/2
Accelerate and protect your CDN network with SPDY and HTTP/2 – it can be done with SSL encryption. TLS/SSL encryption makes up for faster content delivery and less bandwidth usage and also gives you the possibility to enable SPDY – one more performance-based protocol. Providers may offer both free and custom paid versions of SSL. Asset encryption can be activated in one click in section Manage -> SSL in the pull zone dashboard.
In fact, you may not even need to enable HTTP/2 and SSL depending on your web service and target audience. Accurate testing will show which delivery method works better in your particular situation. If you develop an e-commerce project, MMORPG, or any other online business connected with financial transactions and sensitive data handling, you definitely need this option. HTTP/2 from the best providers is compatible with different browsers and origin servers.
8. Enable OCSP Stapling
Such option as OCSP Stapling allows shortening SSL connection times by up to 46%. If you don’t protect your assets with an SSL, you should definitely consider that, because only this certificate allows using web performance protocols as HTTP/2 and SPDY and get more user trust. To top it off, your possibility to improve security doesn’t end there – OCSP stapling (TLS Certificate Status Request extension) is a method that can accelerate SSL connections by up to 46%.
9. Learn Caching Headers
The next thing you can do is learn to understand caching headers in order to optimize your CDN strategy. Caching header defines how your content is stored and transferred by CDN network. You can use different handy tools to generate and inspect HTTP responses that have caching headers. A response can show that the asset has been delivered by CDN rather that origin server, how much the asset will live on the CDN before an updated original version is checked, etc.
Suggest using Hurl.it tool for analyzing caching headers – it provides pretty many details on requests. Send a request to your file with the help of this tool and check the maximal age of file, X-cache, etc. Do they correspond to caching rules specified in your control panel?
Please note that in some CDN solutions, edge server start caching a file only after two requests are made. If there’s cache miss, the file should be requested a couple more times. The third time, X-cache must read HIT. If it doesn’t it may mean your CDN is not correctly configured.
10. Analyze CDN Traffic with Raw Logs
Raw Logs help to understand possible problems with content delivery, but many users often overlook this useful tool. With this feature, you have an instant and detailed insight into CDN activity and every request coming through it. It puts prepared data inside your CDN control panel and allows you to filter requests by visitor location, cache status, zone, user agent, PoPs, and so on.
Now when all the above-mentioned steps are made, you need to repeat the process later to make sure CDN work is optimized. Keep in mind that these tips are better to be completed in the order mentioned in the article. However, some of them may not be relevant for your business – every project has its peculiarities. With advanced protocols, compression algorithms, troubleshooting mechanisms and other web technologies you can easily improve your web content delivery strategy.