This article talks about the technology behind multiple hosting servers and how you can use it to make the most of the security and uptime of your site.
Website hosting has essentially become a commodity. There is little difference between one hosting company and the next. Plans and key features are the same and price is no longer a true determining feature. In fact, choosing best web hosting services based on the lowest price can be more costly in the long run regarding reliability issues and possible loss of sales as a result of site downtime.
Selecting a web host from thousands of vendors and resellers can be a very daunting task, which can result in a random approach. But while accommodation may have become a commodity, a distinctive feature that must always be taken into account is reliability.
At the heart of the reliability of any hosting company is redundancy. This ensures that if there is a problem at one point, there will be an alternative that ensures continuity in the most transparent and seamless way possible.
Most hosts use redundant network connections. These are high-speed pipes that route data from the server to your browser. However, redundant "multiple web servers" were extremely rare and very expensive, requiring costly routing equipment previously used only in mission-critical Fortune 500 applications.
However, a very light but little-known domain name (DNS) resource called "round robin" allows the selection and delivery of a specific IP address from a "group" of addresses when a DNS request arrives.
To understand what this has to do with server reliability, it is important to remember that the Domain Name Server (DNS) database assigns a host name to its IP address. Then, instead of using a series of hard-to-remember numbers (IP address), we simply go into your browser http://www.yourdomain.com to access your site.
Now it usually takes at least 2 or 3 days to spread or "spread the word" of your DNS information over the Internet. That is why when you register or transfer a domain name, it is not immediately available to the person browsing the web.
This delay undermined the security benefits of hosting your site across multiple servers since your site would be inactive for a few days if something went wrong with a server. You would need to change your DNS to reflect your second server and wait for days before the change has been picked up on Internet routers.
However, the round robin DNS strategy addresses this situation by mapping your domain name to more than one IP address.
Some hosting companies now employ the round robin DNS technique along with "bug tracking".
The Rotating DNS Rotating Failover monitoring process starts with a web hosting company that configures your site on two or more independent web servers (preferably with different assigned IP blocks). Therefore, your domain name will receive 2 or more IP addresses.
The failover monitor then monitors your web servers by sending data to the URL you specify and searching for a particular text in the results. When the system detects that one of its IP addresses is returning an error and the others do not, it removes that IP address from the list. The DNS then points its domain name to the working IP addresses.
If any of your IPs are online, they will be restored to the IP group. This effectively and securely keeps your site online even if one of your web servers is down.
The average time to detect and recover from failures with a system like this can be as low as 15 minutes. This time varies according to the speed of your site and the nature of the failure, and also how much time it saves (stores) your ISP's DNS information.
The time it takes for another ISP to store its cached information can be handled in the failover monitor by downloading the time to live (TTL) cache setting. These are the settings that other ISPs will use to determine how long their DNS information is stored.
Of course, you should take into account the frequency with which data is synchronized between the servers in your site. This will be the responsibility of the hosting company, and this can be tricky when it comes to databases and user sessions.
Expensive hardware-based failover monitoring systems that point to a virtual IP address for other ISPs, while behind the scenes multiple unique IP addresses on different servers, of course, the most "elegant" solution for hosting multiple servers.
In this way, the whole ISP issue that caches your information does not come into play.
Therefore, for sites that need to have a real uptime of 99.99995%, without major cash expenses, technology is available and certain systems for tracking property failures are relatively inexpensive to apply.