What is a cloud storage?

With cloud backups (in English Cloud Storage), there are today storage solutions that do not require personal equipment to store and make photos, videos or documents outside of its own system accessible. How does such a service work? And what are the advantages and disadvantages of data backup in the cloud?

What is a backup in the cloud?

Cloud storage is a storage space made available to users on a network (generally internet). This memory is not located on the user's device, but on one or more external servers. In most cases, these are special supplier servers that offer the storage space partly for free, partly for a monthly or annual amount. This model, called public cloud storage (Cloud Storage), makes it possible to modulate both the storage volume and the costs as required.

THE Private cloud storage (Private Cloud Storage) is an alternative located on servers in a private networkgenerally a business network, being only accessible to users of this network. In this case, the operator (the company itself or a third party) has total storage control, but it is also responsible for the necessary equipment and administration. THE Hybrid cloud storage is a third variant, in which the private internal cloud backup solution is linked to external online storage. This is particularly interesting for companies that need a Internal storage space for sensitive data on the one hand and easily expandable and accessible capacities to the public on the other hand.

Whatever the type of cloud storage, the operating principle can be explained as follows: the storage supplier provides a IT infrastructure which allows flexible and secure management of the desired servers. These servers do not work as independent systems as part of the cloud storage service offered, but as a group. To do this, disk space (with other components such as memory or CPU) is virtualized usinghypervisors. These layers of abstraction, which serve as a mediator between real material and the virtual environment, are called Virtual machine monitors (VMM). They are divided into two types, types 1 and 2 hypervisors:

• Type 1 hypervisor (Bare-metal): virtualization software that rests directly on the host system and does not require a preinstalled operating system; requires appropriate pilots (example: Vmware esxi).
• Type 2 hypervisor (hosted): virtualization software that requires a complete operating system and installed on the host; Use the operating system device drivers for hardware access (example: Oracle VM Virtualbox).

Access to virtualized storage generally works with the appropriate software. Public Cloud storage services generally offer not only a web application that can be loaded via the browser, but also specific platform applications used For various peripherals. With this, these users can connect and then access the storage memory. Already saved files can be recovered from any compatible device (computer, tablet, smartphone, etc.), provided that a Active Internet connection exists. For private cloud storage, however, a connection to The intranet or at VPN (Virtual Private Network) is necessary to use the storage solution.

What is the architecture of cloud storage?

Due to the high requirements to which a cloud backup solution must meet, operators depend on a storage architecture that Overlaps traditional storage Based on performance files. This type of storage, based on a system of hierarchically organized files, acts as a correct standard solution, but it is hardly adapted to the management of billions of files, including metadata. Cloud storage services therefore use two alternatives to format the memory of their own servers:

1. THE Block storage (block storage).
2. L'Object Storage (object storage).

Block Storage: the block storage format for structured data

Block storage is a flexible and logically structured storage model in which all data are divided into equal size data blockswhich in turn receive their own addresses. The addresses of physical memory cells are abstract, so that the real location of storage units is not relevant for file storage. The hard drive or server on which the new data is stored, the individual arrangement of the blocks and their mode of access: all this can be easily configured by software. In the cloud, block storage is particularly suitable as a storage format for database applications and other programs working with structured data.

Object Storage: Organization by unstructured data objects

Object storage is a system which, as its name suggests, stores the files in the form of objects, including the corresponding metadata. Thanks to a unique identifier, applications can access each object without a conventional access control system. It is not possible to modify the saved objects, any change leads to the creation of a new object containing the modified version of the original file. This makes object storage the optimal cloud storage format for Online backup and archiving solutions. In addition, object management is well suited to the storage of multimedia files such as music, videos or reading movies alone (for example, when using streaming services).

Whether it is block storage or object storage, operators can choose between SSD or HDD hard drives when assembling cloud storage equipment. SSDs are characterized by better reading and writing speed, but are more expensive than conventional HDD storage supports. Thanks to the virtualization of the storage environment, it is also possible to combine the two types of storage.

The advantages of the Cloud Storage

Cloud file storage can be useful for many reasons. One of the most important advantages of this storage solution: you Savings the purchase and management of your own equipment. If you do not opt ​​for an internal cloud solution, the responsibility for the entire underlying infrastructure is the supplier. If you use cloud storage to save your data, the outsourcing of resources has an additional advantage: that The original and the backup copy are not in the same place. This avoids the total loss of data due to a fire or a flight. Others Cloud storage advantages are :

• Flexibility : You can rent cloud storage space on demand, then give it up as soon as your needs are changing. If you are counting on your own equipment, however, you will not get rid of it easily if you finally need less storage space.
• Scalability : Virtualization of the storage environment allows you to choose the right storage volume, which can also be adjusted at any time if you need more or less space.
• Availability : Public cloud storage is available at any time and from any device, as long as you have an active internet connection. So you can access your files even on the move.

What are the disadvantages of cloud storage?

The Cloud Storage turns out to be an interesting and powerful alternative to traditional storage solutions in many ways. However, there are scenarios in which the backup of files in the cloud can have drawbacks. First, there is the Internet connection dependence Or intranet respective to the internal private cloud server. On the one hand, stability plays an important role here, because if the connection does not work, access to cloud storage will not be possible. On the other hand, the available bandwidth is crucial for the correct transmission of data, which can become problematic, in particular on the mobile network. Cloud storage also presents following disadvantages ::

• Dependence on the supplier : When you choose an external cloud storage solution, you automatically depend on the chosen supplier. Unwanted changes in the offer or interruption of the service are possible not to be excluded.
• Security : sending data through the network boundaries poses security risks, not all suppliers offer TLS/SSL encryption of stored data. In addition, the computer infrastructure used (by the supplier) is an attractive target for attacks.
• Data protection : In terms of data protection, data storage in the cloud is fundamentally problematic. Since the servers of many suppliers are located in different countries, storage of user data is often not compatible with the legal directives of this or that country.

Overview of the main cloud storage suppliers