An easy-to-understand explanation of the pros and cons of CDN adoption!
CDN (Content Delivery Network) is a group of servers distributed around the world that provide high-speed delivery or provision of content on the web. Nowadays, CDNs are being adopted and used almost everywhere in high-traffic websites and applications.
CDN can be used in conjunction with various services.
For example, the CSS framework 'Bootstrap' provided by Twitter allows you to build a website using the framework and JavaScript or jQuery. By using CDN and Bootstrap together, even beginners can easily build accelerated websites.
For those considering adopting a CDN, we will explain the advantages and disadvantages of CDN, which enables high-speed delivery of content in partnership with various services, to increase understanding of CDN.
index
5 advantages of adopting a CDN
Three Disadvantages of Adopting a CDN
finish
5 advantages of adopting a CDN
We introduce the structure and five advantages that enable fast delivery of CDN.
CDN enables fast transmission of content, allowing users of websites or video sites to watch without delay or interruption, helping to improve UX (user experience).
To realize high-speed delivery, there is a cache mechanism. This is explained in detail in the next chapter.
☑︎｜①Improved web page speed
☑︎｜②Leads to cost savings
☑︎｜③ Reduce the burden on the origin server
☑︎｜④ Certain security measures are possible
☑︎｜⑤ One of the SEO measures
①Improve the speed of web pages
First, the advantage of CDN is the fast delivery of content introduced from the beginning.
There is a caching mechanism in place for the reason that it can accelerate the display speed of the website.
How CDNs work
Here we explain how CDNs work. A CDN is a network that mainly consists of two servers.
Origin Server
This is the server that hosts the original files for your content. On-premise or cloud is used.
Cache Server
A group of servers distributed throughout the world. Content is delivered from the cache server closest to the reader.
The first viewer's request reaches the origin server, and the data is cached (replicated/stored) in the cache server. Second and subsequent viewers will serve data from the nearest cache server.
How Acceleration Cache Works
Caching reduces the distance between viewers and servers, and shorter distances deliver content faster and with better quality.
② Leads to cost savings
Introducing a CDN can often result in cost savings across your server network.
Introducing a CDN reduces data transfer volume as data exchange only occurs when it reaches the origin server.
Additionally, with the CDN's load balancing method, the origin server usage does not increase due to scale-up and server usage fees can be reduced.
③ Reduce origin server load
As mentioned earlier, CDNs have a cache mechanism, so when other users in the same region are watching, it will be forwarded from the cache server so they can watch it. With this structure, access to the origin server is reduced and the burden is reduced.
In addition, CDN is configured using a load balancer in the data center to efficiently process and distribute the load even when traffic surges, so companies providing high-load services can use it with confidence. .
④ Certain security measures are possible
It is also effective as a security measure against server attacks, which have recently been on the rise. In particular, DoS attacks/DDoS attacks aim to bring down a server or website by sending a large number of requests, but by introducing a CDN, the down risk can be reduced and security risks can be avoided.
⑤ Becomes one of SEO measures
The reason CDN is said to be one of the SEO measures is due to the judgment made by Google's algorithm.
Page display speed is known to be an important indicator of SEO evaluation, so improving page display speed with a CDN will increase SEO evaluation and lead to higher ranking in search results.
Three Disadvantages of Adopting a CDN
We have introduced the benefits of using CDN so far, but there are also disadvantages to be aware of when using it.
Here are three points you might want to know before introduction.
☑︎ | It takes time for site changes to reflect.
☑︎ | Possible caching incident
☑︎ | Log file may not exist
It takes time for site changes to reflect.
The network has a mechanism called DNS that links IP addresses with domain names, which are addresses on the Internet.
IP address domain name
192.168.1.1 ○○○○.com/ ○○○○.co.jp, etc.
CDN is also deeply related to DNS, and when changing settings, it takes a certain amount of time to reflect the change in DNS. It's a good idea to check the cache purge rate when deploying a CDN, as being able to quickly purge old content from your cache servers can shorten that period.
Possible caching incident
If a CDN is misconfigured, it can cache and deliver data that should not be cached, known as a common cache incident. In the past, there have been cases where personal information was leaked through large-scale flea market services.
In order to prevent such cache accidents, it is essential to establish a system or method to prevent accidents in advance through a systematic approach rather than a casual introduction, so as to establish correct standards for design and settings and ensure proper operation. .
Log file may not exist
If you use a CDN, access logs will accumulate more on the cache server than on the origin server, so your logs will need to go to the CDN.
Some CDN services do not provide access logs.
Additionally, the method of providing logs may be limited. When introducing a CDN, it is necessary to check in advance whether it is possible to select a method of acquiring logs and a location to store them.
Conclusion
CDN has some disadvantages when using it, but it can strengthen essential items in operating a web service, such as improving response speed, reducing costs, and security measures.
When introducing a CDN service, we recommend that you carefully check the specifications, cache deletion speed, log provision method, etc. of each CDN service before making your selection.