NAS scale-out storage: definition, operation and benefits of horizontal scalability

Scale-out storage is a type of NAS (network-attached storage) architecture based on interconnected arrays. This type of storage allows the storage capacity of an enterprise IT system to be expanded at will as needed, without limits and without the need to anticipate future expansions. It offers horizontal scalability, as opposed to vertical scale-up. Learn more about the definition, operation, and benefits of scale-out storage.

In the past, in order to ensure that sufficient storage space was available for expansion, companies had no choice but to to purchase berries from larger storage facilities than they needed. However, it is difficult to accurately predict the expansion of a business. It is possible that the expansion will not take place, or that it will be less than expected. In fact, a waste of money and resources often took place.

Scale-Out NAS Storage: what is it, what is it for?

Fortunately, this problem has largely been solved with the emergence and democratization of so-called scale-out storage. Scale-out storage is a Network Attached Storage (NAS) architecture based on interconnected bays with their own resources. Depending on the needs, it is thus possible to increase the storage space by adding more units.

If the storage limit is reached, or if the company wants to increase the performance of its system, it is possible to to easily add a bay to increase the total capacity of the network. Then simply configure the new bay. This way, there is no need to anticipate future expansions. This type of scale-out architecture reduces the amount of initial investment.

In addition, whatever the evolution of storage needs, it is possible to increase the disk space limitless or almost limitless. Even if there is a sudden huge increase in demand, just add as many berries as you need. This considerably increases the flexibility of the company. This type of storage architecture is therefore ideal for meeting the challenges posed by big data.

scale out nas operation advantages

Scale-Out Nas Storage: how does it work?

To increase the storage capacity of a scale-out system, clusters are added to the system. It is possible to add as many clusters as you wish according to the needs of the company. Each clustered node added to the scale-out NAS allows for an increase in load.

Each unit, also known as a node, offers a certain storage capacity. In general, this capacity depends on the number of physical disks. The node can also have its own processing power, and input/output bandwidth. Thus, adding a unit increases the storage capacity, but can also increase the performances of the system.

As a general rule, nodes are x86 servers embedding an operating system and storage. These servers are linked together by an external network. It is also possible to connect them via a high-speed backplanealso known as a backplane. This is what allows intercommunication. Thus, the users manage and administer the cluster. as if it were a single system.

The data stored on the system is managed with a global namespace, or with a DFS (Distributor File System) distributed file system. This is what allows nodes to be connected without the need for them to be located. in the same physical location.

Scale-Out Storage vs Scale-Up NAS Storage, Vertical Scalability vs Horizontal Scalability: Benefits and Interests

storage scale out vs. scale up scalable horizontal-vertical

The ability of storage systems to scale up in size or volume, i.e. to adapt the system to an increasing need for capacity, is referred to as scalability. Thus, a distinction is made mainly between two different methods of scalability.

The oldest evolutionary technique is scale-up. It is a form of vertical scalability. In concrete terms, scale-up consists of increasing the capacity of computer hardware or software by adding resources to the physical system. For example, this may involve increasing the processing power of a server to make it faster. In storage systems, this means adding units such as disks to the system to increase capacity.

Originally, the NAS was based primarily on vertical scale-up. Capacity could only be increased by adding additional systems to an existing architecture. Specifically, a scale-up NAS system includes controllers also known as “NAS heads”.. These controllers have access to predefined amounts of CPU and memory resources. NAS heads also have access to a predetermined number of disk slots.

Thus, devices share system resources. The control function does not increase with storage capacity. In fact, the performance of a scale-up NAS tends to degrade as more storage units are added. If the limits are reached, the only way to continue to increase capacity and performance is to deploy a new system that the company will have to manage separately. This is the main weakness of scale-up storage and vertical scalability.

In the case of the horizontal scale-out, it is possible to link several entities with their own controllers so that they function as a single logical unit. The nodes don’t even have to be in the same geographic location. Thus, the entire system can be managed simultaneously and it’s possible to increase the capacity ad infinitum… without performance degradation. This is the advantage of scale-out NAS storage over scale-up NAS.

The disadvantage of scale-out NAS storage is that it requires a greater network connectivity. Also, the need for energy and cooling systems may be greater. Beyond a number of clusters added to the NAS, however, power costs are reduced compared to scale-up.

Thus, due to its many advantages, scale-out storage may well become the standard in external storage systems. However, in the long term, it is more likely that the standard will become the capable of adapting in several dimensions Scale up, scale out, and scale linearly (horizontal, vertical and linear scalability). This type of system offers even more flexibility.

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