Exploring the Key Features and Types of Clusters in IT Services

Server wires

The old and familiar expression “The customer is always right” has acquired a new life in the provision of IT services. And, indeed, almost every service company is faced with the need to cater for its customers 24/7, and it does not take into account activities related to infrastructure maintenance, predictive and preventive work and eliminating emerging problems.

In this regard, companies are increasingly turning to server clustering. This approach allows provider to create a single group of several nodes, which, in turn, will ensure their security and safety.

Both public and dedicated nodes can be involved in the process of creating clusters. Obviously, clusters associated with public nodes will suffer from overloads, poor performance and, most importantly, carry high security risks. In turn, dedicated cluster allows company not only to avoid all these problems, but also to function under established client control.

Defining a cluster

The definition of a cluster is not difficult to understand, since cluster is a highly loaded system that can include one or several machines. Such a definition immediately points to one of the main features of the cluster, namely high load, which means the number of 10k or more transactions in the network. In addition, the cluster must have:

  • reliability (failure tolerance),
  • scalability (have parallel VS distributed systems),
  • ability to balance loads,
  • ability to “hot” replace components.

Types of scalability

Speaking about scalability, it should be noted that two strategies can be considered on the way to achieving its desired value. The first of these is the “vertical scaling” strategy, which suggests using simple actions to achieve the goal. That is, by taking an old computer to work and investing certain financial resources in refurbishing it, you can end up with a super modern machine. The second strategy – “horizontal scaling” – also involves investing financial resources, but it has its own characteristics.

Firstly, with horizontal scaling, the number of nodes in the network increases so that the same task is performed by several machines, and, secondly, the load is parallelized. Both the first and second strategies have their positive and negative nuances.

Thus, vertical scaling is easily feasible, mainly depends only on the availability of the necessary finances, does not require changes in the software, and, accordingly, greater user knowledge. However, vertical scaling has its natural limits, which reduces its effectiveness, and often turns this super computer into just an expensive piece of hardware if it breaks down.

With horizontal scaling, there is a linear increase in performance, which means almost infinite scalability. In general, this requires at least two machines (nodes), and their cost does not play a big role, which indicates a cheaper process.

Due to the fact that the nodes are independent of each other, it becomes possible to quickly replace them. However, to implement node communication when scaling horizontally, the software must be significantly changed. This approach leads to the need to have qualified specialists, as well as to a longer maintenance process when troubleshooting breakdowns.

Types of clusters

Of course, achieving scalability is not the only important goal of server clustering; some other features of clusters were listed above. Therefore, based on the tasks that must be solved with the help of IT infrastructure, several types of clusters can be distinguished.

All types of clusters are headed by the three most powerful and productive super computers in the world, which are located in the USA, Japan and Finland. There is a group of clusters that belong to the type designated by the abbreviation HA (High Availability). These clusters are resistant to various failures and include a fairly large number of nodes in their system.

The next group of clusters belongs to the type of “cluster farms” and is characterized by the ability to evenly distribute the load between nodes. A group of clusters, classified as a computing or HPC Clusters, has the ability to divide computing tasks into parallel threads, maintaining unified coordination of actions and high performance of operations.

In Conclusion

In conclusion, it should be noted that not all types of clusters were mentioned above; their number is not limited to this. It should also be recalled that clusters can be created both on physical servers and on virtual machines. In addition, there are also various options for those software solutions that can be used for clustering.


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