POWER > Business Strategy > ROI

Why Clients Are Saving Money From Scaling In With Power Systems

Illustration by Benoit Challand

Scalability is critical to managing systems well. Over the last several years, CIOs have weighed the cost advantages of scaling out versus scaling up when expanding capacity to handle growing workloads. Making a choice to either scale up or scale out has been difficult for many CIOs as they must balance capacity with cost. However, a third option called scale in gives CIOs a cost-effective way to scale flexibly and dynamically using IBM Power Systems* technology.

Scale up and scale out each have advantages and disadvantages. Scale up is a system with a single LPAR and single operating system instance that’s often running on a larger computer. Essentially, you’re scaling up a single application or middleware instance, explains Linton B. Ward, IBM Distinguished Engineer and chief engineer of IBM POWER* workload-optimized systems. To use a real estate analogy, scale up is like a big box store with a lot of interior space and no partitions.

However, as application tiers became available, it wasn’t necessary to use a very large single operating system. Instead, a grouping of smaller computers could be used to run multiple operating system instances to scale out the application tier. Scale out is now synonymous with deploying applications on a group of small servers. It was developed as a solution to server capacity outstripping the needs of a single image application. As a result, virtualized deployment has become the dominant pattern, Ward says. Scale out is like a group of individual stores lined up on a street.

Neither scale out nor scale up alone adequately serve the needs of today’s enterprises, which are seeing the expansion of applications including systems of engagement, mobile, analytics and big data requirements. For instance, in a scale-out scenario using multiple small servers, you might have to configure too much memory on the individual servers to handle the data workload. While scale out allows you to run multiple applications, you end up expanding the number of boxes in your data center rather than consolidating equipment. Further, there’s no option in a scale-out deployment to pool memory or CPU resources across servers.

Enterprises must be able to expand capacity and run multiple operating system instances and applications in a single box. That’s what scale in provides. It’s the best of scale up and scale out, harnessing Power* technology’s capability to manage complex workloads with ease. Scale in is like today’s malls, where a single building houses many stores and the structure can be adapted to suit the needs of individual tenants by moving walls and fixtures. A scale-in system may have multiple servers, but they’re aggregated into a bigger box.

“With scale in, you’re able to have multiple virtualized logical partitions and run multiple applications within the same scale-up server,” Ward says, noting that the server can have a single large image or it can use virtualization to share resources and run them. As capacity needs exceed that of a single system, then a group of scale-in systems can be leveraged.

Too much memory isn’t a problem when using scale in because all memory resides in a single server, enabling it to be allocated more efficiently. You can run multiple applications deployed on a single physical server with scale in too, reaping benefits from this configuration. “By allocating CPU, memory and I/O resources appropriately, you can achieve a lower overall cost—both for the resources and for managing those resources in a scale-in environment compared to deploying a single application to a single physical server,” Ward says. Because most enterprises operate in a dynamic world, additional advantages are found by allowing resources to be shared and allocated in a dynamic way. Scale in improves responsiveness too.

Shirley S. Savage is a Maine-based freelance writer. Shirley can be reached at savage.shirley@comcast.net.

comments powered by Disqus



2019 Solutions Edition

A Comprehensive Online Buyer's Guide to Solutions, Services and Education.

IBM Systems Magazine Subscribe Box Read Now Link Subscribe Now Link iPad App Google Play Store