Should you choose a public or private cloud?

cloud infrastructure

Striking a service-level agreement with a cloud provider is part of using a public cloud. Credit: rvlsoft

Now that cloud computing is no longer a novelty, enterprises that have decided to adopt the technology need to figure out whether to go with a public or private cloud infrastructure. A third way is to adopt a combination of both types — a secure, portable and fast hybrid cloud.

It may come as a surprise, but the list of key factors that enterprises must weigh when choosing among these three options does not include the characteristics of the data that would be stored, said Charles Burns, a research vice president at cloud consultancy Saugatuck Technology.

“Specific factors about the data — such as volume, file type, etc. — are not the most important factors to consider when selecting a location for that data,” Burns explained. Instead, the decision on where to locate data should be governed by usage attributes, such as:

  • Frequency of access.
  • Level of performance or response required.
  • Location of applications — whether in-house or in-cloud — that use, create and modify data.

Options in the cloud

Storing backup data in a public cloud, for example, is a cost-effective solution for these type of large, but infrequently used files — as long as the cloud provider can provide the level of security desired by the file owner, Burns said.

“On the other hand, a large file with high usage by multiple apps running within the customer’s in-house infrastructure is probably best located on an in-house private cloud or traditional infrastructure to avoid transmission and latency delays,” he added.

The hybrid cloud model can be attractive to organizations that want to use their own IT assets as well as those offered by providers to develop the most flexible and cost-effective environments. Burns pointed out that IT administrators who are moving in the direction of a hybrid cloud should expect to see the same service levels for applications and workloads as they do in a private-cloud environment.

Factors worth examining

Conducting a thorough examination of requirements for service levels, performance and availability is critical to finding the best cloud infrastructure, he said. Burns also recommends that enterprises examine the following areas to determine the initial and reoccurring costs related to each:

  • Servers and memory
  • Data uploading, storing, accessing and updating
  • Networks, including downloading data
  • Optional infrastructure for higher availability
  • Supplemental services for managing the infrastructure or workload

The final factor for enterprises considering whether to partner with a cloud provider is the service-level agreement, or SLA, which sets performance expectations and contingency plans in case of unforeseen circumstances. There is no such thing as a one-size-fits-all agreement, as risk tolerance and pressures to drive down costs vary from enterprise to enterprise.

“The most obvious tradeoff for using any cloud offering is the risk of potentially unacceptable service levels versus rewards, such as potentially lower costs or greater flexibility,” Burns said.

Esther Shein
Esther Shein has covered how technology can make businesses more competitive for more than 20 years. Her work has appeared in ComputerWorld, BYTE and Information Week.
Esther Shein
Tags: Cloud Computing,Technology