Difference between revisions of "Cluster"

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== Computer cluster ==
 
== Computer cluster ==
  
In computing, a '''[[Computer cluster|cluster]]''' is a group of interconnected computers (often called '''[[Node (computer science)|nodes]]''' or '''[[Server (computing)|servers]]''') that work together closely. From the outside, they often appear as if they are a single, more powerful system.
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In computing, a '''cluster''' is a group of interconnected computers (often called '''nodes''' or '''servers''') that work closely together. From the outside, they often appear as a single, more powerful system.
  
The main reason to build and use a [[Computer cluster|cluster]] is to achieve better [[Performance (computing)|performance]], higher [[High availability|availability]] (meaning more reliable, with less downtime), or greater [[Scalability|scalability]] (the ability to handle more workload) than a single computer could provide on its own.
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The main reason for using a cluster is to achieve better performance, higher reliability (less downtime), or greater scalability (ability to handle more work) than a single computer could offer.
  
Imagine you have a big task, but one person isn't fast enough, or if they get sick, the task stops. A [[Computer cluster|cluster]] is like having a team of people work on the same task or set of tasks. If one person gets sick, another can take over, and the team can finish the work faster together.
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Imagine you have a big task. If one person isn't fast enough, or if they get sick, the task stops. A cluster is like a team of people working on the same task. If one person gets sick, another can take over, and the team can finish the work faster together.
  
 
=== How Clusters Work ===
 
=== How Clusters Work ===
  
[[Computer cluster|Clusters]] rely on three main things:
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Clusters rely on three main components:
  
1.  **Multiple Computers (Nodes):** These are standard computers or [[Server (computing)|servers]], often with similar hardware, that are linked together.
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Multiple Computers (Nodes): These are standard computers or servers, often with similar hardware, linked together.
2.  **A [[Networking|Network]]:** The computers are connected by a network, which can range from standard [[Ethernet]] to very fast, specialized networks that allow the nodes to communicate quickly.
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A Network: The computers connect via a network, which can be standard or very fast, allowing quick communication between nodes.
3.  **Clustering [[Software|Software]]:** Special [[Software]] runs on the nodes to manage them as a single unit. This [[Software]] is crucial for distributing tasks, managing resources, handling failures, and presenting the group of computers as one system.
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Clustering Software: Special software runs on the nodes to manage them as a single unit. This software is crucial for distributing tasks, managing resources, handling failures, and presenting the group as one system.
 
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This software makes the computers cooperate as a coordinated team, not just independent machines.
This [[Software|software]] makes the group of computers cooperate, so they aren't just independent machines connected by a network, but a coordinated team.
 
  
 
=== Types of Clusters ===
 
=== Types of Clusters ===
  
Clusters are often categorized based on their primary goal:
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Clusters are often categorized by their main purpose:
 
 
* '''[[High availability|High-Availability (HA) Clusters]]:''' These clusters focus on minimizing downtime. If one [[Node (computer science)|node]] in the cluster fails (due to hardware problems, [[Operating system|OS)]] issues, etc.), the clustering [[Software]] automatically and quickly shifts the workload to another working [[Node (computer science)|node]]. This process is called [[Failover|failover]]. The goal is to keep important services running continuously, like critical websites or databases.
 
* '''[[High-performance computing|High-Performance Computing (HPC) Clusters]]:''' Also known as Beowulf clusters or supercomputing clusters, these are designed for raw processing power. They link many computers together to work on complex computational problems that would take a single computer a very long time (or be impossible). Examples include scientific simulations, weather modeling, and complex data analysis. The work is often broken into smaller pieces that each [[Node (computer science)|node]] works on simultaneously.
 
* '''[[Load balancing|Load-Balancing Clusters]]:''' These clusters distribute incoming network traffic or workloads across multiple identical [[Server (computing)|servers]]. A [[Load balancing|load balancer]] (either hardware or [[Software]]) sits in front of the cluster and directs requests to the different nodes. This prevents any single [[Server (computing)|server]] from becoming overloaded, improves response time, and increases the total capacity the system can handle. This is common for busy web servers or application servers.
 
  
 +
'''High-Availability (HA) Clusters:''' These focus on minimizing downtime. If one node fails, the clustering software quickly shifts its workload to another working node. This process is called failover. The goal is continuous operation for critical services like websites or databases.
 +
'''High-Performance Computing (HPC) Clusters:''' Also known as supercomputing clusters, these are designed for massive processing power. They link many computers to solve complex problems too large or slow for a single machine, such as scientific simulations or weather modeling. Each node often works on a small piece of the larger problem simultaneously.
 +
'''Load-Balancing Clusters:''' These distribute incoming network traffic or workloads across multiple identical servers. A load balancer (hardware or software) directs requests to different nodes, preventing any single server from getting overloaded, improving response time, and increasing overall capacity. This is common for busy web or application servers.
 
{| class="wikitable"
 
{| class="wikitable"
 
|+ Primary Goals of Different Cluster Types
 
|+ Primary Goals of Different Cluster Types
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! Type !! Main Focus !! How it Works (Simply) !! Key Benefit
 
! Type !! Main Focus !! How it Works (Simply) !! Key Benefit
 
|-
 
|-
| [[High availability|High Availability]] || Keeping services running || If one server fails, another takes over || Reduces downtime, improves reliability
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| High Availability || Keeping services running || If one server fails, another takes over || Reduces downtime, improves reliability
 
|-
 
|-
| [[High-performance computing|High Performance]] || Solving complex problems quickly || Servers work together on parts of the same large task || Increases speed of computation
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| High Performance || Solving complex problems quickly || Servers work together on parts of the same large task || Increases speed of computation
 
|-
 
|-
| [[Load balancing|Load Balancing]] || Handling many requests || Distributes incoming work across servers || Increases capacity, improves responsiveness
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| Load Balancing || Handling many requests || Distributes incoming work across servers || Increases capacity, improves responsiveness
 
|}
 
|}
  
 
=== Advantages of Clusters ===
 
=== Advantages of Clusters ===
  
* **Better [[Performance (computing)|Performance]]:** By combining the power of multiple machines, tasks can be completed faster (HPC, Load Balancing).
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Better Performance: Combining multiple machines allows tasks to finish faster.
* **Increased [[High availability|Availability]]:** Services remain accessible even if individual servers fail (HA).
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Increased Availability: Services stay online even if individual servers fail.
* **Improved [[Scalability|Scalability]]:** It's often easier to add more nodes to a cluster to handle increased workload than to replace a single server with a much larger one (HPC, Load Balancing).
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Improved Scalability: It's often easier to add more nodes to a cluster to handle more work.
* **Cost-Effectiveness:** Sometimes building a cluster of commodity hardware is cheaper than buying one very large, specialized, fault-tolerant machine.
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Cost-Effectiveness: Building a cluster of standard hardware can sometimes be cheaper than buying one very large, specialized machine.
 
 
 
=== Disadvantages of Clusters ===
 
=== Disadvantages of Clusters ===
  
* **Complexity:** Setting up and managing clustering [[Software]] and the interconnected network is more complex than managing a single server.
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Complexity: Setting up and managing clustering software and the network is harder than for a single server.
* **Cost:** While potentially cheaper than one giant machine, you still need to buy, power, and maintain multiple [[Server (computing)|servers]] and the network infrastructure.
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Cost: You still need to buy, power, and maintain multiple servers and network equipment.
* **[[Software|Software]] Compatibility:** Not all [[Software]] is designed to run efficiently in a clustered environment, especially for HPC.
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Software Compatibility: Not all software is designed to run efficiently in a clustered environment.
 
 
 
=== Usage Examples ===
 
=== Usage Examples ===
  
 
Clusters are used in many areas:
 
Clusters are used in many areas:
  
* Large websites and online services (using [[Load balancing|load-balancing]] and [[High availability|HA]] clusters for web servers and databases).
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Large websites and online services (for web servers and databases).
* Scientific research (HPC clusters for simulations and modeling).
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Scientific research (for simulations and modeling).
* Financial trading systems (HA clusters for critical applications).
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Financial trading systems.
* Cloud computing platforms (often built on large clusters of servers).
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Cloud computing platforms.
* Big data processing and analytics.
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Big data processing.
 
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In summary, a computer cluster is a powerful way to use multiple computers together to achieve performance, availability, or scalability goals that a single machine couldn't manage.
In summary, a [[Computer cluster|cluster]] is a powerful way to use multiple computers working together to achieve goals related to [[Performance (computing)|performance]], [[High availability|availability]], or [[Scalability|scalability]] that would be difficult or impossible for a single machine.
 
  
 
=== See Also ===
 
=== See Also ===
  
* [[Server (computing)]]
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*[[Server]]
* [[Networking]]
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*[[Networking]]
* [[High availability]]
 
* [[High-performance computing]]
 
* [[Load balancing]]
 
* [[Failover]]
 
* [[Scalability]]
 
* [[Virtualization]] (A different way to maximize hardware use)
 
 
 
=== References ===
 
 
 
* {{cite web |url=https://www.ibm.com/topics/clustering |title=What is Clustering? |publisher=IBM |access-date=2025-04-25}} - Explanation from a major computing company.
 
* {{cite web |url=https://www.techtarget.com/searchdatacenter/definition/clustering |title=Computer Cluster Definition |publisher=TechTarget |access-date=2025-04-25}} - Technical definition and explanation.
 
* {{cite web |url=https://aws.amazon.com/hpc/clusters/ |title=High Performance Computing (HPC) Clusters |publisher=Amazon Web Services |access-date=2025-04-25}} - Explanation focused on HPC clusters.
 
  
[[Category:Computer clusters]]
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[[Category:Information]]
[[Category:Distributed computing]]
 
[[Category:Parallel computing]]
 
[[Category:High availability]]
 
[[Category:Scalability]]
 
[[Category:High-performance computing]]
 
[[Category:Server (computing)]]
 

Latest revision as of 11:13, 28 May 2025

Computer cluster

In computing, a cluster is a group of interconnected computers (often called nodes or servers) that work closely together. From the outside, they often appear as a single, more powerful system.

The main reason for using a cluster is to achieve better performance, higher reliability (less downtime), or greater scalability (ability to handle more work) than a single computer could offer.

Imagine you have a big task. If one person isn't fast enough, or if they get sick, the task stops. A cluster is like a team of people working on the same task. If one person gets sick, another can take over, and the team can finish the work faster together.

How Clusters Work

Clusters rely on three main components:

Multiple Computers (Nodes): These are standard computers or servers, often with similar hardware, linked together. A Network: The computers connect via a network, which can be standard or very fast, allowing quick communication between nodes. Clustering Software: Special software runs on the nodes to manage them as a single unit. This software is crucial for distributing tasks, managing resources, handling failures, and presenting the group as one system. This software makes the computers cooperate as a coordinated team, not just independent machines.

Types of Clusters

Clusters are often categorized by their main purpose:

High-Availability (HA) Clusters: These focus on minimizing downtime. If one node fails, the clustering software quickly shifts its workload to another working node. This process is called failover. The goal is continuous operation for critical services like websites or databases. High-Performance Computing (HPC) Clusters: Also known as supercomputing clusters, these are designed for massive processing power. They link many computers to solve complex problems too large or slow for a single machine, such as scientific simulations or weather modeling. Each node often works on a small piece of the larger problem simultaneously. Load-Balancing Clusters: These distribute incoming network traffic or workloads across multiple identical servers. A load balancer (hardware or software) directs requests to different nodes, preventing any single server from getting overloaded, improving response time, and increasing overall capacity. This is common for busy web or application servers.

Primary Goals of Different Cluster Types
Type Main Focus How it Works (Simply) Key Benefit
High Availability Keeping services running If one server fails, another takes over Reduces downtime, improves reliability
High Performance Solving complex problems quickly Servers work together on parts of the same large task Increases speed of computation
Load Balancing Handling many requests Distributes incoming work across servers Increases capacity, improves responsiveness

Advantages of Clusters

Better Performance: Combining multiple machines allows tasks to finish faster. Increased Availability: Services stay online even if individual servers fail. Improved Scalability: It's often easier to add more nodes to a cluster to handle more work. Cost-Effectiveness: Building a cluster of standard hardware can sometimes be cheaper than buying one very large, specialized machine.

Disadvantages of Clusters

Complexity: Setting up and managing clustering software and the network is harder than for a single server. Cost: You still need to buy, power, and maintain multiple servers and network equipment. Software Compatibility: Not all software is designed to run efficiently in a clustered environment.

Usage Examples

Clusters are used in many areas:

Large websites and online services (for web servers and databases). Scientific research (for simulations and modeling). Financial trading systems. Cloud computing platforms. Big data processing. In summary, a computer cluster is a powerful way to use multiple computers together to achieve performance, availability, or scalability goals that a single machine couldn't manage.

See Also