In the spring of 2009, it was easy to talk about the hidden costs of cloud storage because providers weren't helping customers to determine the real costs of the technology. But a lot has happened with the pricing and features of cloud storage offerings, and cloud storage providers are now providing tools that estimate monthly costs.
When a potential customer first looks at a cloud storage provider's website, the basic cost per gigabyte of cloud storage will most likely be prominently displayed. For example, the basic cost for Amazon Web Services is $0.15; pricing for Zetta starts at $0.25 and decreases as more data is stored to the cloud; and for archive cloud storage providers that provide additional features like WORM and information lifecycle management, the basic cost is in the realm of $1.00 per GB.
So a potential customer should be able to calculate how much disk storage they need and then determine a monthly cost for storing data in the cloud. While this sounds simple, few providers actually mention that basic storage costs are only part of the picture.
Data migration into the storage cloud
All providers will charge for data transfers in and out of the cloud based on the volume of data transferred (typical cost is $0.10 per GB). Some will also charge for metadata functions such as directory or file attribute listings, and copying or deleting files. While these metadata operation costs are generally miniscule on a per-operation basis (maximum of $0.01 per 1,000 for Amazon), they can add up based on the amount of users the customer has accessing cloud storage data.
Another piece of the cloud storage pricing puzzle is how a customer actually gets to the data stored in the cloud. Some cloud storage providers, including Autonomy Zantaz and Iron Mountain Inc., support private data lines that connect the customer's infrastructure to the cloud storage infrastructure. Others, such Zetta, estimate that telco circuit and cross-connect fees for customer access data will add up to as much as 20% of their total cost per month. Whether or not this will be an issue depends on the type of data storage and access patterns of the customer.
Perhaps the least well understood cost of cloud storage is the mass transfer of data in or out of the cloud. Some providers, like Zetta, don't charge transfer fees for data migration into the cloud. While others, such as Amazon, include a stated pricing plan for large-scale data transfers using a portable medium, charging a time-based fee for the data load and a handling fee for the portable device.
Assessing cloud storage costs upfront
Taking all of this information into account, customers will want to make sure that every cloud storage request counts. Therefore, a data migration plan is crucial and things like virus scanners, indexing services and backup software should be carefully configured so as not to be accessing the cloud storage medium as just another network drive.
As the cloud continues to evolve, cloud storage providers that can provide the most sophisticated cost analysis tools will be best suited to help potential customers accurately determine costs. Yet customers must still look at all potential costs, including transfer, bulk load, network and on-site appliances.