A simplistic definition of the public cloud is that it is one big amorphous pool of storage that exists “elsewhere.” While there are many options available, five of the biggest cloud storage repositories include the following:
- Google Cloud Storage
- Rackspace Cloud Files
- Amazon S3
- Microsoft Windows Azure Blob Storage
- HP Cloud Object Storage
Let’s take a closer look at each of them.
Google Cloud Storage
Google Cloud Storage is said to be a multi-purpose place to store archive data or backups and application data (images for a photo editing app for example). It can also share data via Access Control Lists (ACLs), and it serves and analyzes static data for websites.
The service requires no specialized hardware or software. To get started, you log into the Google APIs Console and enable Google Cloud Storage. Then you’re ready to begin uploading data. It is backed by Google’s global network of servers and delivers 99.9 percent or better uptime, housing data in multiple, redundant data centers.
Pricing is divided into tiers. You pay based on number of TB stored, network egress (rates vary for different parts of the world) and total number of requests. It can get a little involved. Google Cloud Storage does offer a free trial until June 30, 2013, with up to 5GB of storage for your first project that uses Google Cloud Storage.
Rackspace Cloud Files
Rackspace Hosting provides public cloud, private cloud, hybrid hosting and dedicated hosting. Its Open Cloud storage portfolio includes the following:
- Cloud Files is scalable object storage powered by OpenStack. It is online storage for files and media, delivered globally over Akamai’s content delivery network (CDN).
- Cloud Block Storage provides standard volumes for everyday file system needs and SSD volumes for performance databases and other I/O-intensive applications.
- Cloud Backup is a file-level backup tool.
Rackspace offers tiered pricing for its open cloud products. While the Google pricing above does seem a little complex, Rackspace prides itself on pricing simplicity. “I have been using Rackspace for backup for many years now and its service offerings are growing,” said Greg Schulz, an analyst with StorageIO Group. “I like its all-inclusive pricing model where I don’t have to worry about extra fees for access, moving or deleting data.”
Jerry Schwartz, senior product marketing manager for Rackspace, added that these cloud services tend to be utilized for media management (video/audio streaming, website acceleration, and file distribution/downloads), big data and bursting (moving compute or storage workloads to the public cloud when needed for additional capacity).
He said that Rackspace offers better support, more robust infrastructure and stronger SLAs than its competitors.
“We give a 100% power/network guarantee and credits up to 100% of the monthly charges,” said Schwartz.
Amazon Simple Storage Services (S3)
Amazon Web Services (AWS) has a few different cloud storage offerings. Its Simple Storage Services (S3) offers good general purpose storage with multiple availability zones around the world and redundant data centers in each of those zones.
Amazon S3 holds over a trillion objects and regularly peaks at over 800,000 requests per second. It is pay-as-you-go with no upfront payments or long-term contracts. You pay for data stored at the storage tier selected. Incoming data transfer is free of charge.
In addition, Amazon has various other cloud storage options:
- AWS Glacier is for archiving of inactive data.
- Reduced Redundancy Storage (RRS) within Amazon S3 can reduce costs by storing non-critical data at lower levels of redundancy than Amazon S3’s standard storage.
- Amazon Elastic Block Store (EBS) provides block-level storage volumes for use with Amazon EC2 instances.
- The AWS Storage Gateway is a service connecting an on-premises software appliance with cloud-based storage for integration between on-premises IT environment and AWS’s storage infrastructure.
Pricing varies widely. For example, AWS Glacier pricing for inactive data can be as low as 1 cent per GB per month; however, it can be 3.5 to 5 hours before you can access your data, according to Schulz.
“I like that I can pick locations including inside the U.S, or outside, as well as level of resiliency and cost in addition to being able to leverage Glacier for inactive data,” added Schulz.
Microsoft Windows Azure Blob Storage
While Amazon S3 is probably the most well-known public cloud service, it now has some stiff competition. Microsoft Windows Azure Blob Storage, for example, came out ahead of Amazon in storage vendor Nasuni’s Second Annual State of Cloud Storage Report. Azure outperformed S3 to take the top spot using the criteria of speed, availability and scalability. According to the tests, Azure was 56 percent faster in write speed, 39 percent faster at reads and 25 percent faster in average response time.
Windows Azure storage services are said to provide persistent, redundant storage in the cloud. The storage services are split into the Blob service, Queue service and Table service. Azure Blob storage is designed for storing large amounts of unstructured data that can be accessed via HTTP or HTTPS. A single blob can be hundreds of GB, and a single account can contain up to 100 TB of blobs. Common uses include serving images or documents directly to a browser, distributed file storage, streaming video, backup and DR. Pricing is pay as you go with discounts available for long-term contracts.
HP Cloud Object Storage
The HP Cloud is built on open source OpenStack technology. It is composed of several elements. The HP Cloud Application Platform as a Service (PaaS) deals with application development and deployment. HP Cloud Workload Migration Services help users assess, plan and migrate existing production workloads to HP’s public cloud. HP Cloud Object Storage scored second overall in read speed according to the Nasuni report.
“When transitioning production workloads to the cloud, enterprises look for solid service-level agreements, integrated management, provisioning, orchestration and effective customer support,” said Zorawar Singh, senior vice president and general manager, converged cloud and cloud services at HP.
Currently in beta, HP's cloud is moving to a pay-as-you-go model starting at $0.10 per GB per month for at least 99.95 percent availability. It is said to facilitate the transition from one compute instance to another and is best suited to applications requiring frequent data access such as web applications. Until the beta phase is over, the service will be discounted 50 percent.
“HP’s public cloud continues to release services into general availability on a foundation of open source software,” said Carl Brooks, an analyst, at 451 Research.