Comparative Study of Top Cloud Providers on basis of Service Availability and Cost

The term "cloud computing" refers to a place where we can store our important data and use pay-as-you-go computing and networking services without a physical environment. Today's cloud computing provides us with robust computing and storage, high availability and security, rapid accessibility and adaption, ensured scalability and interoperability, and cost and time efficiency. Users in a cloud environment assume that there are endless resources accessible, and they only pay for the resources they really utilize. The number of cloud service providers is growing quickly and they are adding new capabilities as technology advances. However, a cloud consumer may find it challenging to identify the best service provider for their needs. Three cloud service providers—Amazon Web Services, Google and Microsoft Azure—are explored in this study, and a comparison of these cloud service providers is provided. On the basis of service availability, price, pricing structure, data security, operating system, Windows support, free trial, and geographies, the cloud service providers were compared.


Introduction
The National Institute of Standards and Technology (NIST) [16] defines the cloud computing model as "a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g. networks, servers, storage, applications, and services) that can be rapidly provisioned and released with little management effort or service provider interaction" as the most commonly used definition. A distributed system, or cloud, is described as a collection of interconnected, virtualized computer systems that are introduced or dynamically provisioned in accordance with a larger pool of computing resources that are dependent on service level agreements [1]. Companies that offer network services, infrastructure, platforms, software, or business applications in the cloud are known as cloud service providers. Customers can access the cloud services through the data center of the cloud provider through an internet connection, whether they are individuals or businesses. Customers receive cloud solutions from providers in response to their requests [15].

Need of Study
Offering affordable IT infrastructure and services is one of the main responsibilities of cloud service providers. Given the development of Cloud service providers are multiplying quickly as a result of the widespread use of cloud services by consumers. to pick the appropriate service a provider is challenging in light of a customer's business needs. Consequently, comparing several cloud service providers is crucial to both customers and rival businesses.

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To research the various cloud service providers and the fundamentals of cloud computing.

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To compare the Cloud Harmony scores of various cloud service providers for service availability.

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To compare and evaluate the various cloud service providers in light of the various study parameters.

Research Methodology
Both a theoretical and an empirical approach were employed to attain the goals. The comparison of three public cloud service providers-Amazon AWS, Microsoft Azure, Google Cloud, is done using theoretical literature. The analysis of books, journals, research papers, thesis, online studies, etc. that aid in the analysis of cloud service providers forms the basis of the literature survey. Comparison of various cloud service providers based on price, pricing structure, access interface, customer service, documentation, programming languages, data security, operating system, Windows support, free trial, and geographical areas. Service availability of cloud service providers is evaluated using the Cloud Harmony benchmarking provider.

AMAZON WEB SERVICES
In 2003, Amazon was established as a retailer offering computing infrastructure. Amazon originally provided Infrastructure-as-a-Service, but it now also offers Platform-as-a-Service [7]. Amazon begins offering IT infrastructure services in the form of web services in 2006-a practice now referred to as cloud computing. Currently, AWS offers scalable, dependable, and affordable infrastructure that supports hundreds of thousands of businesses in 190 nations worldwide [20]. The four main product categories offered by Amazon are computing, storage, databases, and networking.

Compute
A web service computing tool called Amazon Elastic Compute Cloud (EC2) offers safe, dynamically scaled compute capacity. To deploy and administer instances based on Microsoft and Linux Operating System servers, EC2 offers a web service interface [12]. Amazon Machine Images (AMI), which include an image of EC2 instances, their software, and configuration to create a boot disc for user instances [13], are essential elements of Amazon EC2. New server instances can be acquired and booted in minutes rather than hours thanks to EC2 [12].

Storage
A storage facility called Amazon S3 offers two different forms of storage, namely objects and buckets. Data can be stored and retrieved as objects in buckets and can be retrieved in any quantity from anywhere. Objects can hold a minimum of 1 byte and a maximum of 5GB of data.

Database
According to commercial databases, Amazon Aurora is a MySQL and PostgreSQL relational database that offers excellent speed and availability. When it comes to commercial databases, Amazon Aurora offers up to five times more performance than MySQL in terms of security, availability, and dependability.

Network and content delivery
A user of AWS can deploy AWS resources in a virtual private network using the Amazon VPC area of the AWS Cloud. The entire virtual networking environment is completely in the control of the customer, including the choice of an IP address range, the creation of subnets, and the setup of routing tables and network gateways [21], [7], [17].

Comparing cloud services using a wide range of metrics
In order to compare various cloud service providers, two requirements-functional and non-functionalwere used. The fundamental core functions of the cloud are described by functional requirements. Non-functional requirement that evaluates the efficiency of a service's operation.  [7] Virtual machines High Functional The end user interface for access, configuration, and deployment is known as the access interface. While Amazon AWS offers a command line interface, Windows Azure, Rackspace, and Rackspace provide control panels online. Some services, such as Google App Engine, merely offer developers an application programming interface. In terms of data, infrastructure, and virtualization, security is the primary concern. Cloud service providers need to make sure the applications and customer data are secure. Providers who offer only the most fundamental security capabilities (such a simple firewall) or none at all are seen as poor, whereas those that include security automation are regarded as good [29]. How frequently the services will be available is referred to as availability [22]. Customers have two options for paying for the resources they use in a pricing plan: pay as you go or on a subscription basis. Customers that subscribe on a subscription basis might do so hourly or monthly. Customers must pay whether they use the resources or not. However, with a pay-as-you-go model, customers only pay for the resources they really utilise [18]. Some service providers offer a free trial to try out their products, which is quite beneficial for customers. There is a two-week to one-month free trial period. Some Depending on their country, suppliers offer users free trials. For instance, the IaaS service Zettagrid exclusively accepts Australian customers and offers a 30-day free trial. Free trials are a request-only service offered by some companies, such as virtual-server.net [19].

Service Availability
With the aid of the internet, availability refers to having access to tools, services, and data from any location at any time. How frequently the services will be available is referred to as availability. With a 99.99% SLA (service-level agreement), the service will be unavailable for approximately 4 minutes every month (30 days per month) and for approximately 50 minutes annually [11], [22]. The study measures service availability using benchmark provider Cloud Harmony. Volume 4, Issue 6, November-December 2022 7 According to service availability, AWS provides 99.99% service availability

Cost Comparison
Each cloud provider's costs are determined by the amount of virtual machines used. The cost of the virtual machine and the cost of the block storage are combined to get the monthly cost for each category of virtual machines for each cloud service provider.