Ken Willett

Healthcare IT, integration, and making patient care better

What Is Cloud Computing, Anyway?

“Cloud Computing” has become a common buzz-phrase in Healthcare IT over the past few years, and as often happens with jargon like this, the definition becomes fuzzier the more people use it. This ambiguity makes it hard to really discuss the pros and cons of different remotely hosted architectures.

In common usage now, Cloud Computing or Cloud Hosting tends to mean an application is hosted remotely and accessed via an Internet connection. But the original usage of the term was much more specific: hosting of multiple instances of an application or applications on a set of servers, using Virtual Machine technology.

Prior to the Cloud explosion, remotely hosted applications generally had a set of servers for each customer. If the resource requirements for a particular customer were small, having its own servers would be very expensive. Conversely, if resource requirements grew beyond the capabilities of the current servers, an expensive hardware upgrade was required. Virtual machines allow the resources for the application to be initially limited, then smoothly increased as needs change, and a virtual machine containing the customer’s application and data can be transparently moved to new hardware.

This approach works extremely well for applications which were originally designed to support one customer. Each customer has their own dedicated computing environment in the same way as if they had their own servers: their own copy of the operating system (e.g., Windows Server), their own version of the application, and their own database. However, not all internet hosted applications operate this way. Highly scalable systems, for example Facebook and this blog site (WordPress), use a different architecture referred to as a “multi-tenant architecture”.

A multi-tenant system is designed from the ground up to support a large number of customers. There is a single instance of the application (perhaps spread across multiple servers for performance and availability) and an integrated data management system. Unlike cloud applications where a new virtual machine is created and configured for each customer, a multi-tenant system usually just requires a small amount of registration data to set up a new customer.

Multi-tenant systems minimize the per-customer maintenance work, because software updates apply to all customers immediately. Operations that cross customer boundaries, such as reporting, monitoring, and communications with other systems are simpler to implement in a multi-tenant system.

The EMR-Link lab hub system that Ignis Systems has developed is a multi-tenant system, supporting thousands of users in an integrated architecture. We believe that this is the best architecture for scalability and for data distribution from hundreds of labs and radiology services to all our providers.

So, when you look at a system that uses the term “cloud”, you may need to dig a little further to understand what that means for your particular needs, since not all applications referred to as cloud-based have the same characteristics. And a cloud solution may not be the best fit in all cases.

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