How can one ensure uninterrupted availability of a website irrespective of Internet issues or a DDoS attack from a single host? One option is to select a reliable hosting provider with 100% uptime, but another approach is to purchase hosting from two different companies and implement round-robin DNS. However, in the case of a server failure, 50% of clients will be directed to the fallen server while DNS records are being updated. This poses a potential risk as access to the fallen server may be restored during this time. Can anyone provide guidance on addressing this issue? Thank you in advance.

Do you believe that the host has specialized servers that can handle your application without issues, while VPS will not?

Is it necessary to update DNS? In the worst scenario, you can reboot and turn it into a proxy, unless the option below is executed:

Install 2+ load balancers designated by DNS records. The load balancers have already selected actual backend servers, and they can even look at the same servers as duplicates.

---

Typically, simple server duplication or one server is sufficient in 99% of cases. Although failsafe measures are great, more interesting things can be done without the need for implementation. Servers usually fail due to load, and such problems can be resolved from the opposite end.

CloudFlare is free, and even if it's messed up, everything will be fine. CloudFlare handles all traffic, effectively removing the problem. Additionally, static content is partially cached.

In the paid modes, cached pages will still be displayed even if there is a server crash.

The approach of using a reliable hosting provider with 100% uptime is a solid foundation, but it's not a complete solution on its own. While a reputable hosting company can provide robust infrastructure and strong security measures, there's always the possibility of unforeseen events or targeted attacks that could still disrupt service.

Implementing a round-robin DNS strategy, as you mentioned, is a good way to introduce redundancy and failover capabilities. By distributing traffic across multiple servers hosted by different providers, you can mitigate the impact of a single point of failure. However, you're right to be concerned about the potential risk during the DNS record update process.

To address this issue, I would recommend considering a more comprehensive high-availability (HA) solution. This can involve the use of a Content Delivery Network (CDN) and/or a load-balancing service, such as those offered by cloud providers or specialized HA platforms.

A CDN can help distribute your website's static content (e.g., images, CSS, JavaScript) across a global network of edge servers, ensuring fast response times and reducing the burden on your origin servers. In the event of a server failure or DDoS attack, the CDN can continue serving content from its distributed network, minimizing disruption to your users.

Integrating a load-balancing service can take the redundancy and failover capabilities to the next level. These services can monitor the health of your servers in real-time and automatically route traffic away from any failed or overloaded instances, ensuring seamless failover without the need for manual DNS updates. Some popular load-balancing options include Amazon Web Services' Elastic Load Balancing, Google Cloud Load Balancing, or specialized services like Cloudflare or Fastly.

By combining a reliable hosting provider, round-robin DNS, a CDN, and a load-balancing service, you can create a robust and highly available web infrastructure that can withstand a wide range of potential disruptions, from internet connectivity issues to targeted DDoS attacks. This multi-layered approach provides redundancy, failover mechanisms, and load-sharing capabilities to ensure your website remains accessible and responsive, even in the face of challenging circumstances.