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Whether backing up corporate servers or processing the next big data project, cloud storage emerges as an enticing option for enterprises. Cloud storage providers like Amazon Glacier and Simple Storage Service, Google Cloud Storage and Microsoft Azure storage, among others, tout a raft of new services and competitive prices for data reaching into the petabytes. But the choice between cloud and on-premises storage is not an all-or-nothing proposition.
Cloud storage is scalable by design; businesses can start small with non-essential data sets and expand storage to more critical workloads as it gains expertise and trust. But what do you really need to know when selecting a cloud storage provider? And how much will those choices cost the company? Determining how much storage you need and how much it will cost may sound like a simple equation, but there are many factors to consider. Enterprises must begin any cloud storage evaluation by carefully assessing current and future needs. Cloud storage costs are based on a mix of capacity, traffic and API use.
Calculating cloud capacity costs
Providers build services to be scalable, so there is no need to plan or commit to any pre-determined capacity. Once you set up an account, your company pays only for the storage it uses, which ranges from several terabytes (TB) to petabytes (PB).
For cloud users, the question of capacity is for cost estimation rather than technical preparation. For example, if you expect to store 4,000 GB (4 TB) of data, AWS Simple Storage Service (S3) quotes $0.03 per GB for the first TB and $0.0295 per GB for the next 49 TB. This would cost $118.50 per month for disk space. Google Cloud Storage, by comparison, charges a flat rate of $0.026 per GB, or $104 per month for the same 4,000 GB.
Stop traffic: Consider network usage costs
At first glance, Google appears to be cheaper in the aforementioned comparison, but cloud storage providers also charge for network usage when data is moved out of storage -- putting data into cloud storage is usually free. If your 4 TB of data must be read twice a month (on average), that’s 8 TB per month of network egress traffic.
AWS S3 charges $0.090 per GB to transfer up to 10 TB per month to the Internet, while Google Cloud Storage charges $0.11 per GB for 1 to 10 TB of network egress traffic. Therefore, you need to add $720 per month for AWS storage reads and $880 per month for Google storage reads. The new total storage and data transfer traffic estimate would be $838 per month for AWS S3 and $984 per month for Google Cloud Storage. In this scenario, AWS comes out as the less-expensive cloud storage option. Data transfer costs vary based on the volume discounts and destinations.
API use enters as equation's third variable
API use adds a third set of costs to the cloud storage equation. API requests such as put, get, copy, post, list, delete, restore, and so on typically carry a small cost per 1,000 or 10,000 requests. AWS S3 charges $0.005 per 1,000 PUT requests; Google charges $0.01 per 1,000 PUT requests.
IT teams often overlook the costs associated with cloud storage support plans. Providers such as AWS offer several plans including basic (free), business, enterprise and developer support. Each plan includes varying response times, monitoring and optimization tools, live support availability, and other features to help companies access and resolve cloud storage issues. Business support can add $100 per month to the storage bill while enterprise-class support can add $15,000.
Enterprises should also look at complementary or companion services when choosing a cloud storage provider. For example, a business that runs or plans to run workloads on Amazon Elastic Compute Cloud (EC2) will likely consider AWS S3 for cloud storage. Similarly, Google Compute Engine or App Engine users will likely look at Google Cloud Storage or Datastore first. Providers often design complementary services to interoperate, and services like Google App Engine interact directly with Google Cloud Storage.
Companion services can help lower cloud storage costs. For example, AWS charges $.02 per GB for data transfers to other AWS regions, and transfers to EC2 and CloudFront are free. Similarly, data transfers to other Google Cloud services in the same region are free.
Stephen J. Bigelow is the senior technology editor of the Data Center and Virtualization Media Group. He can be reached at firstname.lastname@example.org.
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