Cloud Storage Service Comparison

No two cloud storage services are the same. Here's how the top three compare.

Public cloud storage services have become a viable alternative to storing your enterprise data on-premise, but every service is different. This cloud storage comparison is intended to help you evaluate the leading offerings.

Gartner's Magic Quadrant for Public Cloud Storage Services, Worldwide defines public cloud storage as "infrastructure as a service (IaaS) that provides object storage services through a REST API using Internet protocols. The service is stand-alone with no requirement for additional managed services… The service price is based on capacity, data transfer and/or other access requests. Stored data exists in a multitenant environment, and users access that data through the Internet or dedicated network connectivity."

Using Gartner's definition there are only three companies offering services to include in a cloud storage comparison: Amazon Web Services, the clear leader, followed closely by Microsoft and then Google. Far behind in terms of completeness of vision and ability to execute are four very well-known names that nonetheless remain niche players in the cloud storage service market: Rackspace, AT&T, IBM and, at the very back of the pack, Verizon.

Notably, prices in the cloud storage market have dropped significantly across the board over the last few years and continue to do so. That means it is almost meaningless to try to assess which service is the cheapest in a cloud storage comparison.

Price-cutting has been accelerated by Amazon's, Microsoft's and Google's introduction of new services in addition to their standard storage services. These services offer ultra-low pricing in return for some compromise in terms of the level of redundancy or availability offered or the time to access the data.

One thing that is very important to include in any cloud storage comparison is information about the location of the data centers where information is stored. This can be a key determinant of whether a particular service can be considered (for regulatory compliance reasons), especially for companies with operations outside the United States. For that reason location information has been included here.

Here's how the three leaders' cloud storage services compare:

Amazon Web Services

Locations: US West; US East and US GovCloud, EMEA (Germany, Ireland), Asia/Pacific (Japan, Singapore, Australia, China — in preview), South America (Brazil)

Elastic Block Storage (EBS)

EBS is AWS' block storage service. It's complicated because different services have different charging structures that may or not include IOPS and I/O requests. Pricing also depends on the region where you want your data stored. The following prices are for US East:

Amazon EBS Magnetic volumes

• $0.05 per GB-month of provisioned storage
• $0.05 per 1 million I/O requests

Amazon EBS General Purpose (SSD) volumes

• $0.10 per GB-month of provisioned storage

Amazon EBS Provisioned IOPS (SSD) volumes

• $0.125 per GB-month of provisioned storage
• $0.065 per provisioned IOPS-month

Amazon S3 file and object storage

Amazon's S3 storage service offers four products: Standard Storage, Standard Infrequent Access (IA) Storage, Glacier Storage, and a newer Reduced Redundancy Storage (RRS).

The first three services can be summarized as follows:

Amazon's Reduced Redundancy Storage (RRS) is a low-cost Amazon S3 storage option that stores data at lower levels of redundancy than Amazon S3’s standard storage. It is nonetheless designed to sustain the loss of data in a single facility.

Total charges comprise capacity charges, request charges and data egress charges to either other Amazon services or to the Internet. Capacity pricing for these services as of November 2015 is as follows:

Microsoft

Microsoft Azure Blob Storage

Locations: North America (multiple) , EMEA (Ireland, the Netherlands), Asia/Pacific (Australia, Hong Kong, Japan, Singapore) and South America (Brazil).

Microsoft's Azure block blob storage costs depend on capacity, volume of storage transactions and data egress in a similar way to Amazon's S3 service.

What's notably different from Amazon's offerings is that Microsoft offers differently priced services based on different redundancy options. (Unlike Amazon, Microsoft has no ultra-low-cost offline storage option equivalent to Glacier, although it seems likely that one will be introduced in the near future.)

Here's a summary of the redundancy options:

Capacity pricing as of November 2015:

Google

Google Cloud Storage

Locations: North America (U.S.), EMEA (Belgium), Asia/Pacific (Taiwan)

Google's cloud storage offerings are simpler than Amazon's and Google's in that there are only three different storage products rather than four: Standard Storage, a slightly lower cost Durable Reduced Availability (DRA) Storage that offers lower availability than Standard Storage, and the very low cost Nearline Storage . This competes with Amazon's Glacier offline storage on price, offering slightly lower availability and slightly higher latency than Standard Storage (time to first byte is typically 2 - 5 seconds compared to Glacier's 4 hours. ) Google does not elaborate on exactly how DRA differs from Standard Storage.

Google's capacity charges are much simpler to Amazon's or Microsoft's because they are flat rate. Total storage costs are made up of this flat rate plus data transfer and egress charges in a similar pricing structure to the one offered by Microsoft.

As of November 2015, capacity charges and availability targets are as follows:

• Standard: 2.6c per GB/month, 99.9% availability
• Durable Reduced Availability: 2c per GB/month, 99% availability
• Nearline: 1c per GB/month, 99% availability

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