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2015/04/27 13:05:17

Public clouds vs Private clouds

Public and private clouds have advantages before each other in the field of security, reliability and scalability. The choice of this or that model depends on those requirements which are applied by the specific organization to the IT infrastructure and also from tasks which face it.

You See Also:

* Cloud computing * SaaS * IaaS

* PaaS


Why cloud computing is so popular?

Because it is convenient. Or, speaking more specifically, due to scalability (which allows to maintain the growing loadings and to process large volumes of data), elasticity (it is possible to increase infrastructure power without capital investments in the equipment and the software), payment in process of use (expense optimization, further failure from a capital expenditure) and self-services (consumers request and receive required resources in a few minutes).

What types of cloud services happen?

There are two main types — a public cloud (providing cloud services and resources to a large number of clients, using public big data processing centers) and a private cloud (own cloud infrastructure of the organization). The public cloud allows to transfer all corresponding expenses to operating costs and provides quick and inexpensive start of IT solution. In case ofa private cloud the capital investments remain — but also full control of IT infrastructure is retained.

However approach of Oracle is based on a concept of a hybrid cloud — consolidation of private and public clouds in which cross controlled use of data and applications between them is implemented. Oracle implements in a hybrid cloud the concept of cloudbursting — an opportunity to prevent effects of an overexpenditure of capacities of a private cloud at peak load due to use of a public cloud. The hybrid cloud is very convenient for development and testing, integration of B2B-solutions, implementation of products, exacting to IT resources, test operation of the new systems.

It is important to remind that the cloud is not just a certain number of files on a certain server once again. The cloud is a cloud when are automated provision of services, their administration and payment. That is why we say that the private cloud is an automation, deployment and management of IT systems. The companies with big, difficult IT infrastructure understand it especially well because it is impossible to manage such infrastructures without automation — that is why the private cloud is especially relevant for such companies.

Who needs it?

Categories of users who receive the greatest benefit from a private cloud are:

  • Developers — they can quickly and without bureaucracy to unroll development environments.
  • Testers — they can quickly clone large databases.
  • Administrators of Oracle — they can spend less time for accomplishment of routine tasks.
  • Chief financial officers — thanks to a payment system in process of use they have a transparent picture of costs for IT.
  • Heads of the companies which receive the flexible IT infrastructure which is easily adapted to changes.
  • Divisions which constantly need mass deployment of jobs — for example, training centers (each new pupil receives the virtual machine).

Good candidates for use of DBaaS are the companies which:

  • use many databases and consolidations can take advantage;
  • regularly execute cloning of databases;
  • need detailed control of use of IT resources by consumers;
  • have problems at the moments of peak loads and need an option of increase in computing power for such situations;
  • wish to simplify administration of IT infrastructure, to standardize it, to transfer costs from maintenance of infrastructure to its development;
  • want to ensure the high level of reliability and safety of applications, but have no enough experienced database managers in the state;
  • do not wish to contain big IT department at all;
  • want to increase efficiency of use of the big park of the equipment;
  • IT service providers whose clients are interested in a hosting of a DB, application servers and virtualization;
  • use an IT hosting;
  • provide cloud services as telecom providers.

Selection terms

The last several years the debate over cloud computing in the market do not cease: what advantages of cloud computing does create for business? And if after all to make the choice for benefit of cloud services, then what model in each case is optimal: private cloud (private cloud), public cloud (public cloud) or hybrid cloud (hybrid cloud)? Disputes around this question occasionally remind political: pros and cons are at supporters of all models, and protect them occasionally with serious obstinacy. The truth, as usual, is located in the middle: in each case the choice for benefit of existence or lack of a cloud and also modifications of infrastructure, should be defined after consideration of all set of factors.

In this article first of all differences of two models conceptually opposite each other are considered are a private and public cloud. As hybrid environments are a compromise between two of these models, and variations of such hybridization great variety, it does not make sense to stop in detail on pluses and minuses of hybrid cloud simply.

Public cloud

In a public cloud IT services and infrastructure resources are provided over a global network the Internet. The possibility of use of infrastructure of third-party provider creates a set of opportunities for effective loading of resources and their redistribution. Big minus consists that public clouds are much more vulnerable in comparison with private. Public clouds, nevertheless, are the acceptable choice when:

  • The standardized application is used by a large number of people, an example – e-mail
  • It is necessary to test work of a program code or applications
  • The SaaS-application from the checked provider having the worked strategy in security is used
  • It is required to support possibilities of own infrastructure in a situation of peak loads
  • Cloud services are necessary for ensuring joint work

Pluses of a public cloud

  • Public cloud services are distinguished by big simplicity and efficiency of use.
  • Access to applications does not require anything any more, except as stable Internet connection.
  • Tariffing of services is performed monthly and based on annual plans, the system of rates flexible, and, as a rule, providers implement discounts at payment for a bigger period.
  • Use of a public cloud – a real opportunity to reduce the IT budget due to lack of expenses on "iron" and software.
  • Flexibility and scalability: the pay-as-you-go model allows to pay so many resources how many it is required at present, and quickly to regulate this parameter up or down.
  • Reduction of time for infrastructure maintenance: in standard, not cloud, the environment of change of settings of applications or servers can take hours, days or even weeks, in virtual environment it occurs much quicker – in a few minutes.
  • As application servers are in a cloud, the risk simple business processes because of server accidents is excluded. Virtual servers of providers are most often configured on powerful physical base, placed in large data centers where possible time of idle times is calculated for minutes a year.
  • Use of public clouds and lack of contact of users with a difficult computer hardware allows to refuse services of IT specialists in the specific organization.
  • The lack of long-term contracts and cross liabilities with the IT companies allows to change cloud provider as required.

Minuses of a public cloud

  • The main minus of a public cloud is the lack of opportunities for control from the organization: the operability of services is completely subordinated to tretyestoronny provider.
  • Slow speed: performance of public cloud services directly depends on stability and the width of transmission of Internet connection, in certain cases data transmissions can be slow. When operating in large volumes of data public clouds do not sustain the competition to private on performance.
  • Investments in IT infrastructure in addition are also capital investment, in case of use of a public cloud investment with a backlog on the future is just impossible, tangible assets are not purchased.
  • Weak security of data - one more characteristic of public cloud environments. What efforts would not be made by provider in the field of security, protection of a private cloud will always be much more reliable.

Private cloud

In a private cloud services and infrastructure resources are interconnected based on private network. Such model guarantees significantly higher level of security and control, but expenses on program and the hardware when using such approach are considerable in comparison with public clouds. Private clouds are the acceptable choice when:

  • All business is built on applications and data, the level of security requirements of information – critically high
  • Business belongs to one of those industries where requirements to security and confidentiality of information are historically very high (war industry, a public sector – a striking example)
  • The company is rather big in order that creation of own modern DPC was profitable

Pluses of a private cloud

  • Comparably there are more opportunities for control in comparison with a public cloud just because all components of IT infrastructure remain on the party of the organization. Thus the companies can monitor and manage a cloud environment more effectively.
  • The high level of security is provided that a consumer of service is the unique organization so all infrastructure can be optimum configured under the existing security requirements of data. It does not mean, however, that public clouds are not safe in general.
  • In some countries there is prohibition on personal data processing of citizens outside the country so for those businesses which operate with personal data the appeal to services of the international providers with data centers abroad – is just impossible.
  • High performance of private clouds is connected, in particular, with the fact that they operate within internal fayervol and means of protecting of perimeter of corporate network so the transfer of data passes much quicker.
  • The configurability of private clouds also remains at the high level.
  • At implementation of a private cloud the efficiency of work of IT department increases — at any time at the request of business it can deploy the necessary service in 5-10 minutes. IT specialists only lift the virtual machine from a template and set necessary service while the company with traditional IT infrastructure should order the server, install on it the software and applications and to connect it to network. Only one supply of equipment time takes 6-8 weeks.

Shortcomings of private clouds

  • Considerable expenses at all stages of lifecycle of a cloud, from implementation before support of working capacity. At a stage of deployment investments into the equipment and the software are required.
  • The private cloud needs to be managed that involves costs for administration and involvement of competent IT specialists.
  • In comparison with a public cloud risks of loss of operability of services and or data loss because of physical threats is much more essential to infrastructure.
  • Sooner or later the organization can face a capacity ceiling when resources of the infrastructure created under a private cloud it can appear insufficiently.
  • Perhaps, need of costs of big human and material resources for its creation and further work remains one of the most essential shortcomings of a private cloud.

5 steps to the choice of model of a cloud

In practice the choice of specific cloud model is performed on set of all parameters: the company defines as far as it is ready to renounce risks in the field of security for benefit of, for example, low cost and scalability. Or questions of control over a cloud are how critical for it that despite higher cost to select private model.

The following 5 criteria are obligatory to consideration when choosing model of a cloud:


If it is about small business with the small budget, then it is worth beginning consideration with proposals of public cloud providers. Most likely, among them there will be optimal on a ratio a price / computing resources. In that case it is not necessary to be spent also for purchase of hardware-software base, and for compensation of IT specialists. If it is about the enterprise of the average level more largely which has the IT means budgeted for a year, the private cloud can even be cheaper public in the long term: in order that to define it, it will be required to make calculations. Bigger control over operability of a cloud and the agreement on the level of service (SLA) written under the specific company will be plus to a financial component.


If from the enterprise compliance to any regulated standards of security is required, for example, it can be relevant for state companies, then it is necessary to consider first of all private cloud models as only such scheme of work of a cloud can provide individual "settings" of data protection. Public clouds more are suitable for processing not critical and not sensitive to date leaks, in that case information can be trusted third-party provider of a public cloud safely.

Control over the equipment

Users of services of SaaS have no control over the equipment and virtual servers based on which applications work if they are in a public cloud on the party of provider. If requirements of the organization consist in total control of information resources and permanent monitoring of infrastructure, then such requirements cannot be implemented in a public cloud, and private - will become the most probable choice.

Control over idle times

In a private cloud of the enterprise can constantly keep track of availability of all services to end users, using management tools and administration cloud resources shifting load of "healthier" or free computing resources. In a private cloud it is more convenient to test new applications, algorithms and scenarios of work based on virtual environments that does not prevent work of the main business applications at all. If the company has no such requirements, it can consider the possibility of use of a public cloud.

Management of SLA

For rendering public cloud services the standard agreements SLA are used, exceptions can be made only for really large customers. The company can register such SLA which is required to it in a private cloud, having obtained individual conditions and guarantees from provider.

Opinions of the famous experts

Many companies use private clouds independently to be convinced of all advantages of this technology without risking the data. At the same time private clouds can be less reliable and protected, than public services.[1] than This point of view adhere Jason Bloomberg who somehow said that private clouds bring more problems, than it is worth it. In the book The Agile Architecture Revolution: How Cloud Computing, REST-Based SOA, by and Mobile Computing Are Changing Enterprise IT Jason designated several reasons for which public clouds – the best choice for the organizations.

It is possible not to agree with Jason's opinion, these are rather subjects for discussion, than the final truth. But these statements really are worth it that to discuss them.

1. The tendency to use in private clouds of older technologies, than in public is observed: You can spend for purchase hardware and the software for the private cloud tens and hundreds thousands dollars, but try to find the company which is ready to do it annually.

2. Public clouds transfer a capital expenditure to operational: You have no need to build own data center, you can pay money only for use.

3. At public clouds the best coefficient use: When using a private cloud of your company anyway it is required to build and support the systems from different servers to maintain peaks of requests. In a public cloud from you it will be required to pay more only directly at the peak moments.

4. Costs for infrastructure in public clouds for new projects are lower: When using private clouds urgent expansion of infrastructure for unplanned projects can be required.

5. Public clouds provide the best scalability: Unlike a private cloud, you will never be able to develop all resources of the public platform.

6. Public clouds save the companies from need to penetrate into functioning of data centers: Construction of a private cloud requires deeper immersion in work of data center, than in a case from normal server.

7. Publiny clouds are won on economic indicators: Any private cloud will not wash away to compete at use cost with Google or Amazon.

8. Security in public clouds is increased as they constantly should fight against attempts of the hacker attacks: In recent years thousands of hackers tried to crack the Google and Amazon platforms. Providers of public clouds are ready practically to everything.

9. Public clouds involve the best specialists in the field of security: They have an opportunity to select the best experts in the field of security, to pay them a high salary and to treat them as to the most important component of business which they in fact also are. Whether the normal organization will be able to provide the same?

10. Private clouds suffer from excessive self-confidence: "If something is in internal network, it is rather protected!" That says it all …

11. Employee competence of a private cloud is unknown: In your organization there can be a great number of talented and experienced employees, but whether data protection is the main profile of its business?

12. In private clouds tests for protection against unauthorized access are insufficiently often and qualitatively carried out: Even if you hold testing of the applications and networks on a regular basis (that for the normal organizations a rarity), everything that you will be able to learn, it your system directly at the time of check is how protected.

Meanwhile, the vice president of Oracle corporation Doug Hughes considers (information of spring of 2014) that the decision on transition to use of public cloud services also cannot be simple. As a rule, the decision instant comes when at the enterprise carry out audit of an obsolete equipment. But it is necessary to approach it taking into account the direction of business, a maturity of the company and its IT service and requirements of the legislation, but not to consider that failure from cloud computing without fail will lead to failure. The final decision on implementation of cloud solutions will depend on where and as it is supposed to implement them, Hughes believes.

From the financial point of view one of the main advantages of use of public cloud services is that expenses on them entirely belong to current (OPEX), but not to capital (CAPEX), Hughes noted. Implementing solution on own material resources attracts reference of expenses capital, and at implementation of a private cloud expenses share between current and capital. Public clouds solve also a problem of a software update as responsibility for it is transferred to provider of a cloud service.

Five "not" a private cloud

Implementation of cloud services is caused by rapid penetration of virtualization on the enterprises and is method to increase efficiency of delivery of IT services, Tom Bittman, the analyst of Gartner specifies (the publication in Network World, the USA). But behind hype accurate determination of a cloud is lost. Bittman gives simple advice to the buyer who appeared in confusion: "The IT department should not give in to hype, and be focused on projects of creation of private clouds as the most relevant now for business". Bittman listed several widespread inexact ideas of a private cloud.

The cloud is not only virtualization

Having just installed a hypervisor on the server, you do not receive a private cloud yet. Though virtualization is a crucial element of cloud computing, in itself it is not a cloud. Virtualization allows to integrate in a pool and to provide resources. But that technically your environment could be considered as cloud, also other components, such as automatic providing services and scaling option are necessary. The term "private cloud", unlike public or hybrid, belongs to the resources used by the only organization or means that cloud resources of the organization are completely isolated.

Cloud — not necessarily an economy source

One of the main delusions consists that the cloud will save money. Economy is possible, but it is not obligatory attribute of a cloud. Technologies of automation, the most important element of network for a private cloud, can demand impressive investments in many cases. As a result there is an opportunity more effectively to distribute resources, and some organizations thanks to it reduce capital costs of the new equipment, thereby reaching economy. Gartner considers that not economy, and the possibilities of fast adaptation and dynamic scalability allowing to increase the speed of implementation of new services should be the main incentive to implementation of cloud model.

Private cloud not always locally

Many are convinced that the cloud can be called private, only if it is in a data processing center of the organization user, and the public cloud is what is provided by third-party service provider. However many suppliers offer nonlocal private clouds, i.e. select resources to the only customer, excepting sharing of one pool by several clients. "The cloud is called private on its privacy, but not on where it is unrolled who owns it and bears responsibility for management" — Bittman emphasizes. Some, for example, can place the DPCs with hosting providers or integrate resources of different customers in a pool, but isolate them from each other using VPN.

The private cloud is not only infrastructure services

Popular belief that the private cloud serves only for providing services of virtual infrastructure. However on the basis of a private cloud applications and platforms in the form of service and also many other types of services can be implemented. Meanwhile IaaS is valid the most fast-growing scope of private clouds, but not necessarily the most important.

"IaaS is providing the most low-level resources of DPC in idle time for use to a form, but fundamentally the principles of work of IT department from it do not change" — the analyst believes. PaaS, it continues, allows the organizations to create any applications expected execution in cloud infrastructure. PaaS are provided from public and private clouds, at the same time the hosting of service of application development is performed or in your own DPC, or in the selected environment at provider.

The private cloud can stop being private

For many organizations a private cloud — the natural first step to mastering of cloud computing. It provides advantages of a cloud — speed of reorganization, scalability and efficiency, saves from some security risks, potential and real which are characteristic of public clouds.

Agreements on the service level and standards of security will reach a maturity, and failures and failures will be minimized. Over time, predict in Gartner, the majority of private cloud environments will become hybrid — the using also public cloud resources. So, your present private cloud can stop being like that tomorrow.

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