5 secrets to fast and reliable cloud services
We often come across low-cost, low-grade competitors who offer cloud and free-bundled DNS services out of a single server farm or, even worse, providing DNS services hosted on the same server or the same network, sometimes even at the end of a very remote xDSL line. Under these conditions, using a single location for a DNS system, long latency and any temporary network failure cause disruption of all services for a domain, including the potential loss of email.
A good Domain Name System (DNS) and a network of globally distributed application servers help build fast and reliable cloud services.
- When looking for an always-on internet solution, the ideal is to use redundancy to protect against network failures and denial-of-service (DoS) attacks. This usually means using redundant DNS and servers hosted at different locations, possibly routed by other AS (Autonomous Systems). Downtimes with significant cloud and CDN providers often occur because their systems are not designed to survive a single point of failure inherent in their architecture.
- Any cloud service provider should offer their clients multiple (more than two, redundant DNS servers on different network segments and at various physical locations, with inherent redundancy in all potential single points of failure. Anycast DNS services can also be a more expensive (sometimes less effective) solution to this problem.
- Do you remember the notorious technological problems of HealthCare.gov (the US President Obama Health Insurance Marketplace)? When too many users access an application simultaneously (i.e. any line application or a web server), the server or the network may become overloaded. The result is increased latency (slow or no response) and potential data loss. By carefully engineering online applications so that the number of servers can be dynamically increased, the application load and the number of users may be distributed among different servers at various geographical locations, and more transactions can be managed simultaneously. On the other hand, when a single data centre or server fails or if a router or the network is overloaded, all online services will become slow or unreachable.
- By increasing the number of geographical locations where multiple origin servers are hosted, it is also possible to “load balance” and improve the reliability of the whole system. If one or more servers or network segments fail, a globally distributed load-balancing system will continue to provide service until there is at least one server online. To this extent, the most common load-balancing or passive CDN solutions relying on a single origin server are invalid.
- Configuration and de-configuration of servers in case of network or server problems should be fully automatic and require little or no human intervention after initial set-up. A global load-balancing mechanism like WorldDirector provides a fully redundant and distributed DNS system,m including content acceleration.