Databases Reference
In-Depth Information
TABLE 6.1: Similarities and Differences between Cloud and Grid Systems
Perspective
Grid
Cloud
Bottom up: From existing
Top-down: From interface design
Design
heterogeneous resources to
towards hardware and computing
development of abstraction
resources development and
layers for general usage.
management.
Business
Project-oriented: Users have
Consumption basis: Customers
Model
an allocation of service
pay providers for the amount
units that they can spend.
of services used.
Support different types of
Support different types of applications:
Application
applications: From high performance
However, it is unlikely to support HPC
Model
computing (HPC) to high
applications. Applications can be
throughput computing (HTC).
loosely coupled, transaction-oriented,
and interactive.
Compute
Batch-scheduled: Users submit batch
Interactive: Resources are shared by
Model
jobs (via GRAM) to request
all users at the same time.
resources for a period of time.
Virtual data in data grids: Virtual
Data are shared between cloud and
Data
data captures the relationship
client computing
Model
between data, programs, and
computations and prescribes various
abstractions within the data grid.
6.1.2.2
Cloud Services
Cloud services are usually provided at three different levels, namely infra-
structure, platform, and software. Infrastructure as a Service (IaaS) offers
hardware, software and other equipment to deliver application environments
with a resource usage-based pricing model. An example of this type of service
is Amazon's Elastic Cloud Computing (EC2). These services provide public
access to computing and storage resources under pay-per-use model. In IaaS,
the cloud infrastructure scales according to the application resource require-
ments.
Platform as a Service (PaaS) provides users the capability of developing
and deploying custom applications on the cloud. PaaS provides an integrated
environment for software development and testing. An example of PaaS is
Google's App Engine, which enables users to build web-based applications for
systems that run Google applications.
Software as a Service (SaaS) focuses on providing special-purpose software
that consumers can access through the Internet based on a usage-based pric-
ing model. An example of this type of service is Salesforce.com. Salesforce.com
offers CRM (Customer Relationship Management) services. At present, Sales-
force.com also delivers IaaS and PaaS services.
