What is the difference between Cloud Grid and Cluster

Question

What is the difference between Cloud  Cluster and Grid  Please give some examples of each as the definition of cloud is very broad  As answered in another question  can I call Dropbox  Gmail  Facebook  Youtube  Rapidshare etc  a Cloud   What are the examples of Cluster and Grid as well

User · Accepted Answer

Cluster differs from Cloud and Grid in that a cluster is a group of computers connected by a local area network (LAN), whereas cloud and grid are more wide scale and can be geographically distributed. Another way to put it is to say that a cluster is tightly coupled, whereas a Grid or a cloud is loosely coupled. Also, clusters are made up of machines with similar hardware, whereas clouds and grids are made up of machines with possibly very different hardware configurations.

To know more about cloud computing, I recommend reading this paper: «Above the Clouds: A Berkeley View of Cloud Computing», Michael Armbrust, Armando Fox, Rean Griffith, Anthony D. Joseph, Randy H. Katz, Andrew Konwinski, Gunho Lee, David A. Patterson, Ariel Rabkin, Ion Stoica and Matei Zaharia. The following is an abstract from the above paper:

Cloud Computing refers to both the applications delivered as services over the Internet and the hardware and systems software in the datacenters that provide those services. The services themselves have long been referred to as Software as a Service (SaaS). The datacenter hardware and software is what we call a Cloud. When a Cloud is made available in a pay-as-you-go manner to the general public, we call it a Public Cloud; the service being sold is Utility Computing. We use the term Private Cloud to refer to internal datacenters of a business or other organization, not made available to the general public. Thus, Cloud Computing is the sum of SaaS and Utility Computing, but does not include Private Clouds. People can be users or providers of SaaS, or users or providers of Utility Computing.

The difference between a cloud and a grid can be expressed as below:

Resource distribution: Cloud computing is a centralized model whereas grid computing is a decentralized model where the computation could occur over many administrative domains.
Ownership: A grid is a collection of computers which is owned by multiple parties in multiple locations and connected together so that users can share the combined power of resources. Whereas a cloud is a collection of computers usually owned by a single party.

Examples of Clouds: Amazon Web Services (AWS), Google App Engine.

Examples of Grids: FutureGrid.

Examples of cloud computing services: Dropbox, Gmail, Facebook, Youtube, RapidShare.

User · Answer

Cloud  is simply an aggregate of computing power  You can think of the entire  cloud  as single server  for your purposes  It s conceptually much like an old school mainframe where you could submit your jobs to and have it return the result  except that nowadays the concept is applied more widely   I e  not just raw computing  also entire services  or storage       Grid  a grid is simply many computers which together might solve a given problem crunch data  The fundamental difference between a grid and a cluster is that in a grid each node is relatively independent of others  problems are solved in a divide and conquer fashion   Cluster  conceptually it is essentially smashing up many machines to make a really big  amp  powerful one  This is a much more difficult architecture than cloud or grid to get right because you have to orchestrate all nodes to work together  and provide consistency of things such as cache  memory  and not to mention clocks  Of course clouds have much the same problem  but unlike clusters clouds are not conceptually one big machine  so the entire architecture doesn t have to treat it as such  You can for instance not allocate the full capacity of your data center to a single request  whereas that is kind of the point of a cluster  to be able to throw 100  of the oomph at a single problem

User · Answer

Cloud  the hardware running the application scales to meet the demand  potentially crossing multiple machines  networks  etc    Grid  the application scales to take as much hardware as possible  for example in the hope of finding extra-terrestrial intelligence    Cluster  this is an old term referring to one OS instance or one DB instance installed across multiple machines  It was done with special OS handling  proprietary drivers  low latency network cards with fat cables  and various hardware bedfellows     We love you SGI  but notice that  Cloud  and  Grid  are available to the little guy and your NUMAlink never has been

User · Answer

my two cents worth    Cloud refers to an  imaginary easily scalable  unlimited space and processing power  The term shields the underlying technologies and highlights solely its unlimited storage-space and power     Grid is a group of physically close-by machines setup  Term usually imply the processing power  ie MFLOPS GFLOPS   referred by engineers  Cluster is a set of logically connected machines device  like a clusters of harddisk  cluster of database   Term highlights how devices are able to connect together and operate as a unit   referred by engineers

User · Answer

Cloud is a marketing term  with the bare minimum feature relating to fast automated provisioning of new servers  HA  utility billing  etc are all features people can lump on top to define it to their own liking   Grid  Computing  is an extension of clusters where multiple loosely coupled systems are used to solve a single problem  They tend to be multi-tenant  sharing some likeness to Clouds  but tend to rely heavily upon custom frameworks that manage the interop between grid nodes   Cluster hosting is a specialization of clusters where a load balancer is used to direct incoming traffic to one of many worker nodes  It predates grid computing and doesn t rely on a homogenous abstraction of the underlying nodes as much as Grid computing  A web farm tends to have very specialized machines dedicated to each component type and is far more optimized for that specific task   For pure hosting  Grid computing is the wrong tool  If you have no idea what your traffic shape is  then a Cloud would be useful  For predictable usage that changes at a reasonable pace  then a traditional cluster is fine and the most efficient

User · Answer

There s some pretty good answers here but I want to elaborate on all topics   Cloud  shailesh s answer is awesome  nothing to add there  Basically  An application that s served seamlessly over the network can be considered a Cloud application  Cloud isn t a new invention and it s very similar to Grid computing  but it s more of a buzzword with the spike of recent popularity   Grid  Grid is defined as a large collection as machines connected by a private network and offers a set of services to users  it acts as a sort of supercomputer by sharing processing power across the machines  Source  Tenenbaum  Andrew   Cluster  A cluster is different from those two  Clusters are two or more computers who share a network connection that acts as a heart-beat  Clusters are configurable in Active-Active or Active-Passive ways  Active-Active being that each computer runs it s own set of services  Say  one runs a SQL instance  the other runs a web server  and they share some resources such as storage  If one of the computers in a cluster goes down the service fails over to the other node and almost seamlessly starts running there  Active-Passive is similar  but only one machine runs these services and only takes over once there s a failure

[cloud] What is the difference between Cloud, Grid and Cluster?

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