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The Benefits of Going Virtual

Quoting Express Computer

We know that if business continuity is an organisation’s key objective, operations must be up and running 24x7. Best practices suggest using geographic redundancy to establish multiple data centers or sites located in different geographic regions, each with replicated applications and data. Do you need to replicate everything? Not necessarily—just those things that are deemed mission critical. Some organisations will feel that the bulk of their applications and data are mission critical, whereas others will have a smaller subset.

You can implement geographic redundancy in a number of ways. You can deploy multiple sites and use a product such as Veritas’ Smart Location or EMC’s Replication Storage to duplicate applications and data, which is a significant investment. Today, most IT professionals still build redundant sites for backup and manually manage data replication and failover to the secondary site when needed. The company not only has its site sitting inert as an insurance policy, but also as a nonperforming asset. By virtualising data center resources at both sites, you can turn non-performing assets (with the exception of a disaster) into an ongoing available asset that will function in a distributed scenario to achieve maximum reliability and performance regardless of location.

For example, in an active-active data centre configuration (a design that provides backup, disaster recovery, and continuity of operations), you could do data replication, upgrades, and maintenance on a more-frequent basis, increasing your overall uptime and time-to-market for services. There are other benefits to virtualisation when you look at the data centre itself. If you need maximum availability and high performance for your applications and data, you can deploy a reliable midrange server with RAID and redundant power supplies that costs half a million dollars. You’ll still have a single point of failure because you have a single system. You could also achieve your business objectives by throwing expensive hardware at it, trusting that all the components will keep running.

A better practice is to virtualise your server and application resources—a more cost effective architecture. Instead of deploying an expensive mid-range system, virtualise multiple, low-cost, high-performance servers with applications and data, so when one server fails you are not impacted. This gives you the opportunity to achieve high availability and performance without breaking the bank.

Considerations for virtualising your data centre

It starts with the application. Can this application be deployed in a manner that it can be virtualised? Does it support clustering or are there tools that help it support clustering so each application instance recognises state? If so, that application is a great candidate for virtualisation within the broader context of the application-delivery network framework.

Can the underlying applications be replicated in real time between redundant sites so that they can resolve requests at any site at any time, ensuring that data is current? If you can’t replicate the data in real time, there might still be an opportunity to virtualise redundant sites if the data being served doesn’t require up-to-the-minute freshness. There are many scenarios where that does makes sense. What day-old data is acceptable?

Ultimately, you have to look at the underlying application infrastructure to determine what you can virtualise. The same is true for virtualising connectivity and links. You also must consider the amount of data and performance during the replication process. In this case, the primary challenge is not the bandwidth or link capacity—the challenge is how much data can be concurrently transferred or put into the pipe while eliminating protocol communication overhead. We’ve seen customers with OC-3 connectivity between data centres with replication processes using only a fraction of that pipe. They have much data to transfer and it just trickles into the pipe, so replication literally takes days to complete—it’s not efficient.

Fortunately, there are solutions that use symmetrical WAN acceleration to mitigate this situation, so replication processes that took days to finish now get completed in hours. That’s a better model and a better use of the underlying infrastructure, which includes available bandwidth.

The benefits of data centre virtualisation

From an architectural standpoint, there are many benefits to virtualising resources that deliver applications. The savings are profound, such as better use of infrastructure, 99.999 percent availability, and simplified management. It boils down to better operational efficiency.

With virtualisation, there’s efficiency in the underlying hardware requirements. In essence, you need less hardware or less-expensive hardware to do the same work. You can get five times the performance for a third of the cost when you compare a midrange system to a modest server farm.

If I can put 10 low-cost servers in a virtualised resource pool, I have five to 10 times the power of the most powerful midrange system at a third of the cost. By virtualising my servers, I realise tremendous cost savings and have a much better architecture for availability and ongoing maintenance. If I need to bring one server down, I don’t impact the others, and I can gracefully add and remove systems to support my underlying architecture.

For tasks such as ongoing maintenance and management, you can realise significant efficiencies. For redundant active-active data centres managed by an intelligent DNS system, I can easily bring down one data centre for maintenance without affecting the others or impacting users.

The benefits of virtualisation run the gamut: ongoing maintenance and management, reduction of hardware acquisition costs, and better architecture for availability, security, and performance. This is why virtualisation is becoming the standard for designing IT resources for the future.

Virtualisation really isn’t a new concept, though. What is new is thinking about all the points in the WAN and LAN infrastructure where you can realise virtualisation benefits regardless of where you started. Consider the need for employees worldwide to securely access your network and applications at any time. Sometimes sites go down for maintenance, connectivity problems, or disasters. If you provide worldwide access that is only available 95 percent of the time and is under performing 98 percent of the time, you are not achieving your goal of round-the-clock global access.

Here, virtualisation integrated with access technologies (such as SSL VPN) comes into play. Virtualisation of distributed access devices that route users to the best possible site, which hosts your SSL VPN access control, provides access to applications and network resources without any interruption of service.

Routing users to the best available site is completely transparent and does not require client software to be updated or reconfigured, a process that is fraught with problems. Again, virtualisation is a better model. Think about virtualisation from a holistic architectural approach to fully realise its benefits.

Do you need virtualisation?

When you consider virtualising your IT resources, you must consider all critical junctures of your network topology. What is your current environment? Do you have multiple data centres, do you currently multi-home or provision multiple ISP links from different providers? Do you have applications that you want to or can virtualise? Where are your users coming from—the branch office, overseas, or remotely from the road? Are those users private employees, public users, contractors, suppliers, and customers? Finally, what are your business goals, objectives, and SLAs?

All are key questions to ask first if you wish to experience the benefits of virtualising your resources later.

Read the original, here.

Published Saturday, January 13, 2007 2:47 PM by David Marshall
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