You can read about Storage Virtualization here. This page is about cloud storage in general and the types. It is defined as a service model and how you maintain, manage and back it up off site while maintaining accessibility to the users.
In Cloud computing, there are three services models; Public, Private and Hybrid.
Public Cloud Storage
Multi-tenant storage environment and used for mainly for unstructured data. Example of this service is Amazon’s Simple Storage Service (S3) Also known as storage as a service, on-line storage or utility storage on pay per use basis. It is a service used for backing up data as part of a disaster recovery plan DR and archiving applications like email or non-core application data. How CSPs charge for this service is usually on a dollar-per-gigabyte per month.
The table stake of using public cloud storage is the mitigation of risk; the Cloud Service Provider (CSP) is responsible for building and maintaining the infrastructure and the associated CapEX on costs like power, cooling, and maintenance. The Benefit is the organization only pays for what it uses, and it provides scalable resources with a simple click of the mouse.
Private Cloud Storage
Dedicated environment and protected by a Firewall provided by the organization, not a provider. An organization will deploy a Private Cloud environment when they need control and protection around data governance.
In private cloud storage, Object-based storage can meet the requirement because it can store billions of files and data elements that have unique identifiers and can scale to petabytes and exabytes. The following services are commercial grade options.
- Caringo Inc. CAStor
- Cleversafe Inc. Slicestor
- DataDirect Networks Inc
- EMC Corp
- Gluster GlusterFS
- Hitachi Data Systems Inc. Hitachi Content Platform (HCP)
- NetApp Inc. StorageGrid
Hybrid Cloud Storage
The makeup of a Hybrid Cloud Service involves a public and private cloud offering. In the Hybrid cloud storage model, unstructured and archival data is usually in a public cloud. Actively used, and structured data reside in the private cloud.
Risk mitigation of data is the primary factor in choosing a Hybrid Cloud Storage solution. Other factors include compliance and legalities.