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Cloud Computing - Data Storage

Cloud Storage is a service that allows to save data on offsite storage system managed by third-party and is made accessible by a web services API.

Storage Devices

Storage devices can be broadly classified into two categories:
  • Block Storage Devices
  • File Storage Devices

Block Storage Devices offer raw storage to the clients. This raw storage can be partitioned to create volumes.


File Storage Devices offers storage to clients in form of files, maintaining its own file system. This storage is in the form of Network Attached Storage (NAS).

Cloud Storage Classes

Cloud Storage can be broadly classified into two categories:
  • Unmanaged Cloud Storage
  • Managed Cloud Storage

Unmanaged Cloud Storage means that the storage is preconfigured for the consumer. The consumer cannot format nor the consumer can install own file system or change drive properties.


Managed Cloud Storage offers online storage space on demand. Managed cloud storage system presents what appears to the user to be a raw disk that the user can partition and format.

Creating Cloud Storage System

The cloud storage system stores multiple copies of data on multiple servers and in multiple locations. If one system fails, then it only requires to change the pointer to stored object's location.

To aggregate storage assets into cloud storage systems, the cloud provider can use storage virtualization software, StorageGRID. It creates a virtualization layer that fetches storage from different storage devices into a single management system. It can also manage data from CIFS and NFS file system over the Internet. The following diagram shows how SystemGRID virtualizes the storage into storage clouds:

Virtual Storage Containers

Virtual storage containers offer high performance cloud storage systems. Logical Unit Number (LNU)of device, files and other objects are created in virtual storage containers. Following diagram shows a virtual storage container, defining a cloud storage domain:


Storing the data in cloud is not that simple task. Apart from its flexibility and convenience, it also has several challenges faced by the consumers. The consumers require ability to:
  • Provision additional storage on demand.
  • Know and restrict the physical location of the stored data.
  • Verify how data was erased?
  • Have access to a documented process for surely disposing of data storage hardware.
  • Administrator access control over data.
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