Cloud computing represents a new computing paradigm and a further step towards realizing the vision to provide computing resources as a utility similar to the provision of electricity (Buyya et al., 2009). Several Cloud vendors have emerged to date and their services can be classified according to the definition of the National Institute of Standards and Technology (NIST), which makes use of a three layer model (Mell & Grance, 2011): Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS), and Infrastructure-as-a-Service (IaaS). Although the service types are different, all types of Cloud-based resources have five essential characteristics in common (Mell & Grance, 2011):

• Cloud-based resources are automatically provided on-demand, when they are requested by a Cloud consumer.
• Cloud-based resources can be accessed worldwide using standard network mechanisms.
• Cloud-based resources support access in a multi-tenant way.
• The underlying Cloud infrastructure is able to adapt to changing resource demands, i.e., it allows for dynamic up- and down-scaling.
• The resource consumption is measured and serves as a foundation for elastic pricing and billing models.

Taking these properties into account and focusing on data storage, Cloud-based solutions provide several advantages in contrast to former data centre solutions. Especially, the following three aspects can be mentioned (Armbrust et al., 2010):

• The appearance of an infinite amount of available computing resources provisioned on demand.
• No up-front commitment by Cloud users required in terms of reserving the estimated maximum of resource utilisation in advance.
• Dynamic resource allocation and release allowing for short-term billing models.

Therefore, a Cloud-based Information Infrastructure is applied within SIMPLI-CITY for the preprocessing, storage, and access of data coming from various, technologically heterogeneous sources.

Thereby is cloud computing not only the common term for public available services. Also private and hybrid concepts exist:

Private cloud: Private clouds can involve pooling computing resources within the enterprise and allocating them dynamically to internal users. Normally, though, dedicated private clouds are provisioned and managed by an outside service provider. These clouds are designed to satisfy the specific needs of corporate customers and to provide ICT services on the fly. Specialized providers with network capabilities can supply private clouds as one-stop, end-to-end solutions. They cover the full range of ICT services and systems, from mobile and stationary devices to connectivity and bandwidth to the integration of ICT into the customer’s business processes. They also guarantee service levels through binding Service Level Agreements (SLAs).

Hybrid cloud: It appears likely that the hybrid cloud – a combination of public and private clouds – will dominate cloud computing in the enterprise space. Providers are already mixing and matching private clouds and public services to create end-to-end offerings. They integrate public clouds mainly to capture certain functions or capitalize on economies of scale. The combination can even enhance security. A public directory service, for instance, lets users easily use and send encrypted or signed e-mails between secured private domains. Essentially, public cloud services connect private clouds and utilize the integrated security technology.

In general there are several new trends in Cloud Data Storage: Enterprises are beginning to see the benefits of using the cloud to harness the business intelligence (BI) in big data. And Cloud computing offers scalability, which makes it a practical vehicle for big data analytics.