Grids and clouds: What's in a name?
Clouds and grids are developing in parallel. What's the difference? How can they complement each other. and how will they continue to change?
First of all, what are they now?
Grids - A grid is a collection of computers, usually owned by multiple parties and in multiple locations, connected together such that users can share access to their combined power.
Clouds - A cloud is a collection of computers, usually owned by a single party, connected together such that users can lease access to a share of their combined power.
Grid computing is a relatively established form of distributed computing, adopted early by the high energy physics community and used now by all kinds of scientists. In contrast, cloud computing has recently experienced a surge and is a service now offered by a growing number of IT companies.
Grids and clouds are much the same: both grids and clouds have adopted the concept of IT “as a service,” although grids are more likely to offer free access to shared resources, while clouds have a “pay-as-you-go” approach.
But grids and clouds are also very different: where grid technology focuses on helping different groups to share access to their shared resources, cloud computing aims to provide IT services to businesses “on demand”.
CLOUDS FOR BUSINESS, SURE, BUT WILL WE SEE CLOUDS FOR SCIENCE?
Cloud computing makes it easier than ever before for businesses to access computing power. But can cloud computing also help scientists? We’re not yet sure.
Researchers have very specific IT requirements that so far have needed special grid-style computing power. But what if Google or Amazon could one day provide a computing cloud that perfectly suited our scientists? Would we still need scientific computing grids?
Some people say that cloud computing will not be able to provide the special services that scientists need for their research. Others say that cloud computing will make it easier for scientists to access the computer power they need.
WHAT DOES ALL THIS MEAN?
Ultimately, each project or person needs to make their own decision about whether to use grids or clouds or both. One thing is sure: both grids and clouds are rapidly evolving technologies that are helping scientists, businesses and individuals to achieve things never before possible. What will happen to these technologies in ten years?
WHAT IS VIRTUALISATION?
Virtualisation allows you to create “virtual machines” or computer “images” that include the applications and operating system of your choice. Multiple virtual computers can run inside a single physical machine.
Many clouds use virtual machines as job scheduling units: users can submit their jobs as virtual images that include all the required software and tools. Starting the virtual machine inside the physical machine provides immediate access to these tools, creating the ideal environment in which to work on a job. Any number of virtual machines can run independently on the same physical machine.