The Comparative Benefits Of Private, Public and Hybrid Clouds

Cloud Benefit Highlights

• Overall – you need to balance Cloud v on pemise solutions in an overall application mix
• Security – you need to make sure the legal data jurisdiction issues are addressed by the hosting site
• Elasticity – you need to allow application writers to move easily through test/dev to production and allow for Web scale growth
• Performance  – you need to run applications synchronously or asynchronously at appropriate speeds

Private Clouds Are Expensive, But Ensure The Best Security

CXOs in large companies are often confused about which type of Cloud Computing to adopt within their organisation. We offer here some thoughts about how to evaluate and chose the one that’s right for you. We hope it will help in outlining some essential features of the evolving styles and giving you some criteria for choice.

The largest systems suppliers, such as IBM, HP, Fujitsu are in the process of helping their largest customers build their own private clouds: or, more importantly, modify existing IT systems and data centres to provide more modern experiences for their employees and customers. We define a Private Cloud as being one based exclusively on the user’s own premises. As with each of our examples a comparison of the benefits is shown in Figure 1 (top left) – where a wider the blue plane indicates stronger generic benefits. Our scores are as follows:

• Security 5.0 – the major benefit of this style; there are many health sector, financial and government organisations for which absolute data security requires things to be done in-house
• Elasticity 1.0 – clearly running your own servers, storage and networking will put finite restrictions on scaling out; there are a handful of vendors (Hitachi in the storage systems market for instance) who may install equipment at your site which you pay for only when you use it – in the last recession this was sometimes referred to as ‘on/off capacity upgrade on demand’
• Performance 4.0 – performance can be planned as part of the build out of course, although again it will be limited in comparison with some of the of premise solutions
• Total Cost of Ownership 1.5 – We’ve scored this at 1.5 as you’ll be investing in new systems and processes; there are few examples of ‘spend to save’ in this area

If you’re thinking about building your own Private Cloud you might want to look at our analysis of IBM and Fujitsu, or contact us to talk about other vendor approaches. The system vendors have their hands on other forms of Cloud Computing as well of course. 

Public Clouds Have The Lowest TCO, But Security Is Often a Gating Factor

Early Cloud Computing offerings from Sun, Google and Amazon offered application developers the opportunity to develop applications ‘on the Cloud’ before deploying them. Our interview with Double Take Software demonstrates how a supplier can offer asynchronously replicated servers as an alternative to more expensive in-house fault tolerant solutions. This is how we scored Public Clouds:

• Total Cost of Ownership 5.0 – applications delivered from Public Clouds are almost always the cheapest and have the additional advantage in the recession of being charged on a usage basis: lower
• Elasticity 5.0 – Amazon and Google have massive resources and it is unlikely that you will run out of their capacity to deliver your applications
• Performance 2.0 – currently Public Clouds offer little direct control over resources and there may be long distances between your users and the supplier’s servers, as a result we’ve scored performance lower than
• Security 1.5 – for many organisations Security is a gating factor; financial services companies are legally required to have their systems audited; in many countries your are not allowed

Hybrid Private Clouds Trade Absolute Security For Lower TCO

There are many types (and potential types) of hybrid Cloud Computing, where an organisation keeps control of some – while outsourcing other resources to provide applications to their users. In our model we have two types – one where workloads are shared across the customer’s and supplier’s data centre and the other where the vendor takes over the running of the client’s systems in a multi-tenanted environment. The involvement of the supplier adds the Public, while knowing where the data and processing takes place adds to the Private elements. Hybrid Clouds tend to offer better TCO than Private Clouds and can achieve acceptable levels of security for many companies. In particular:

• The Hybrid Private Cloud, located on and off premise scored almost as highly as the Private Cloud for Security (4.5 v 5.0), although the Elasticity of the system scored 3.0 and the TCO was just 2.0; Performance was highest (equalling that of the other Hybrid type (see below)
• The Hybrid Multi-Tenant Cloud is one where the computing is done exclusively in the supplier’s data centre, sharing many resources with other customers; it has the second lowest score for Security (3.5), but has scored highly in all other categories; the only proviso here is sharing resources; irrespective of legal compliance issues most organisations have steered clear of sharing with others; it will be fascinating to see the extent to which Cloud Computing breaks the mould

These types of offerings (often without Cloud branding) are being offered by many managed services companies; they sometimes represent an extension of existing disaster recovery and backup services and the realisation that data communications can take the place of things such as the physical shipment of tapes. It’s worth pointing out, however, that Cloud Computing will increase the dependence and spending on MPLS and other data networks – especially for mission critical applications. These Hybrid Clouds are perhaps the most interesting, as they will help redefine the barriers between national and international computing over the next few years.

Some Conclusions – Which Style Of Cloud Computing Is Best For You?

Even the most cynical of us are having to come to terms with Cloud Computing, even if we will never need it or can argue that we are already its champion. For those of us that need to evaluate and choose, we’ll need to look hard at the existing IT systems, technical expertise and resources before jumping in. While Cloud Computing is sometimes described as just a delivery mechanism for the ultimate user, you will need to evaluate the generic and specific benefits of these basic styles before you start to invest. Our summary view of the benefits is shown in Table 1.

Table 1 – The Comparative Benefits Of Different Styles Of Cloud Computing

Source: ITCandor, November 2010

In our simple model we haven’t weighted the ‘average’ score and there are a number of other issues we could add to the list of benefits: however we think it’s sufficient to help us see some overall differences. In particular Public is cheapest, but will be avoided by those companies for whom security is a gating function, Private scores highest for security, but has the worst TCO. The highest average scores were the two hybrid models, which offer savings over Private Clouds while retaining adequate levels of security for many. The highest scoring of the four types of Cloud Computing is the Hybrid Multi-Tenant model, where the gating function is the sharing of resources with other users.
Of course there are many other issues to address – the planning, implementation process, choosing a trustworthy supplier, making sure you can move to a different style if necessary at the end of the contract for instance.
Please let us know how you see the choices and whether this post helps by commenting below. We are particularly keen to help users to compare the numerous offerings and approaches of suppliers and to help them in their planning.

ITCandor Acronym Buster

CXO – Chief X (anything) Officer
MPLS – Multi-Protocol Label Switching
TCO – Total Cost of Ownership