A computer cluster, server cluster or server cluster, is a group of independent servers operating as a single system. Discover the definition, operation, advantages, use cases and the French translation of the cluster. We will also discuss the difference between cluster computing and grid computing. Finally, we will discuss the concept of storage clusters for personal computers.
Within a computer system, a cluster of servers is a group of servers and other independent resources operating as a single system. The servers are generally located close to each other, and are interconnected by a dedicated network. Thus, clusters make it possible to take advantage of a centralized data processing resource. A client communicates with the group of servers as if it were a single machine.
Server cluster: how does it work?
As a general rule, a server cluster is consisting of compute nodesof storage nodes of front nodes. Sometimes there are additional nodes dedicated to monitoring.
The nodes are connected to each other by several networks. Administration tasks such as loading systems on nodes, monitoring and load measurement are usually handled by the network with the slowest throughput.
The second network, with much higher bandwidth, joins the first network. Its throughput of up to 40 Gigabits per second. It is based on technologies such as Quadrics, Myrinet and Infiniband.
Programs running on server clusters are based on a Standard API: Message Passing Interface. This API ensures communication between the various processes distributed on the nodes by means of messages.
In case of server failurethe clustering software isolates the system in question. When resources are shared between several tasks, if one server is overloaded, the tasks are shared with another server.
Within a cluster of servers, each server has and manages its own local devices and is based on a copy of the operating system, applications and services it manages. Common devices in the cluster, such as disks and the connection media to access those disks, are owned and managed by one server at a time.
Server cluster: what are the use cases?
Server groups are designed for whose data are frequently updated. They are generally used for file servers, print servers, database servers, and mail servers.
Clusters are increasingly used in the scientific communityto meet the growing need for high-performance computing (HPC). They are also used extensively in the field of digital imaging, for computer-generated images.
Server clusters are also used in the field of management information technology in order to minimize the impact of a possible server failure on the availability of an application. For example, companies are deploying NAS storage networks to implement shared drives.
The peer-to-peer (P2P) networks are increasingly being used as an alternative to server clusters. Their advantage is a significantly lower cost.
Server cluster: what are the advantages?
The advantages of the server cluster are that it offers a high availabilityand sometimes load balancing and parallel computing capabilities. Clusters also allow for easy scalability and resource management (processors, RAM, hard disks, network bandwidth, etc.).
When an error occurs on one of the computers in the cluster, resources are redirected and the workload is redistributed to another computer in the cluster. Thus, clusters guarantee a constant access to resources based server important.
In general, a server cluster allows you to go beyond the limitations of a computer and offers global management. Server clusters also have the advantage of being inexpensive. By using these systems, there is no need to invest in a multiprocessor server. Simply buy small systems and connect them to each other as needed. Clusters therefore offer greater flexibility.
What are the different types of cluster architectures?
There are several types of cluster architectures: single-layer, double-layer, and multi-layer. These architectures are based on the various grouping possibilities of the different layers: enterprise application layer, web layer, presentation layer and object layer. The choice of architecture for an enterprise application depends on the usage model and the type of application.
The single-layer cluster is considered the basic, simplest architecture. Each computer performs all the layers simultaneously, and the load balancer distributes the requests among the different servers in the cluster. This architecture is therefore easy to administer and easy to scale up. However, servers can have uneven load leading to performance degradation. This type of architecture is therefore rarely used for enterprise applications.
In the case of a bundlethe three basic layers are grouped into two logical layers. The web and presentation layers run on separate computers in a web server cluster. It is therefore possible to balance the load on the object layer using replication-sensitive modules.
The multilayer cluster is the most complex architecture, but offers the highest availability. Each layer runs on a separate computer, and forms a cluster with its own computers. Thus, this architecture offers three levels of load balancing. An ideal architecture for applications where the use of each layer is different and groups a large number of clients.
Cluster translation: what do you call a cluster in French?
The cluster translation into French recommended by the General Delegation for the French language and languages of France and the General Commission for Terminology and Neology is “server cluster”. This image speaks for itself, because a cluster actually works like a cluster.
Another translation often used is “computational farm”. The “nodes” are called “nodes”.
Cluster Computing vs. Grid Computing: What are the differences?
The Grid Computing in French, is a virtual infrastructure made up of a set of computer resources. These resources are potentially shared, distributed, heterogeneous, delocalized and autonomous.
This infrastructure is referred to as virtual because the relations between the entities that make it up exist only at the logical level and not on a material level. The grid differs from other infrastructures in its ability to adequately meet requirements such as accessibility, availability and reliability through the computing or storage power it can provide. The grid thus guarantees non-trivial quality of service.
There are several differences between grid computing and cluster computing. When two or more computers are used together to solve a problem, it is called a cluster. Cluster computing is the use of a cluster of servers.
Grid computing also involves connecting multiple computers to solve large problems, hence the frequent confusion between grid computing and cluster computing. The big difference is that cluster is homogeneous, while the grids are heterogeneous..
The servers and computers that make up a grid can run different OSes and embed different components, while the server clusters all have the same components on board and the same operating system. A grid can distribute its computing power, while the machines in a cluster operate as a single unit.
The grids are usually distributed over a LAN, metropolitan area network or WAN. The computers and servers in a cluster are generally gathered together in one place.
Another difference is the how resources are managed. In the case of a cluster, all nodes behave as a single system and resources are managed by a centralized manager. In the case of grids, each node is autonomous. It has its own resource manager and behaves as an independent entity.
What is a PC storage cluster?
In the field of storage technologies for personal computers (PCs), a cluster is a logical file storage unit on a hard disk drive. Each file stored on the hard drive consumes one or more storage clusters.
Clusters in the same file can be distributed to different locations on the hard disk. The traces of the different clusters associated with a file are kept by the FAT (file allocation table) of the hard disk.
When the user reads a file, he gets the entire file without even knowing on which clusters it’s stored. Clusters are managed entirely by the computer’s operating system.
The cluster is not a physical unit. It is not integrated directly into the hard drive. It is a software unit. For this reason, the size of a cluster can vary. The maximum number of clusters on a hard disk depends on the size of the FAT.
In the beginning, under DOS 4.0, FATs were only 16 bits. This allowed a maximum of 65536 clusters. Since Windows 95 OSR2, the 32-bit FAT allows storage of up to two terabytes of cluster data. It is of course necessary that the hard disk has sufficient capacity.
Before FAT support on Windows 95 OSR2a single partition could support a 512 megabyte hard drive. to the max. Hard disks with larger capacity could be divided into up to four partitions. Each partition could support 512 megabytes of clusters.
The problem is even the smallest file consumes an entire cluster. In fact, if a cluster is 2048 bytes in size, even a 10-byte file will consume the entire cluster. Most operating systems offer a default cluster size of 4096 or 8192 bytes.