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This article is from the Summer 2009 issue of Hospitality Upgrade magazine.To view more articles covering technology for the hospitality industry please visit the Hospitality Upgrade Web site or to request a free publication please call (678) 802-5307 or e-mail. | ||
| By Lyle Worthington Virtualization is not a new concept. If you are reading this article then you have experienced virtualization directly in one way or another. If you are a network administrator you�ve undoubtedly worked with virtual LANs, server administrators managing a SAN or a RAID array are taking advantage of storage virtualization, and your e-mail client is using virtual memory. These examples, while seemingly quite different, are all based on the same fundamental concept of virtualization. The concept is simple: take an existing set of resources, divide them into several pieces, and use hardware or software to serve each piece up as a dedicated resource. Server virtualization does just that with your physical servers. Instead of having several moderately powerful servers to handle your applications you purchase one or more extremely powerful servers and divide their resources among several virtual machines (VMs). This is made possible through software, called a hypervisor, running directly on the server�s hardware that tricks each of the VMs into thinking they are running on a dedicated server. Take a look in your server room. Whether large or small, you probably have multiple dedicated servers each running their own set of applications. There are numerous reasons for putting different applications on dedicated servers�perhaps it�s a requirement of the software vendor or your own security policy, or maybe the two applications can�t run on the same operating system. Whatever the reason, you inevitably have one or more racks full of servers running 24/7, each serving just a few purposes, and all sized to handle your peak loads. You end up with a room full of underused hardware, constantly consuming electricity and happily turning it into heat that your HVAC units have to cool. Until recently this waste of resources was a necessary evil, but as hardware prices have dropped and virtualization vendors have become more enterprise-ready that is no longer the case. Virtualization will help you clean up the server room, consolidating many servers into few giving you significant immediate and long-term cost savings.
Studies show that typical organizations use only 10 percent to 25 percent of their available server resources. If this is you, it is not unrealistic for you to put 10 or more VMs on one powerful server, and you could save up to 50 percent on server hardware alone. If you think about it, this number makes sense; you are buying more powerful hardware, but much less of it. Additionally, this one server will pull only twice as much electricity as each individual machine, so you could see an 80 percent reduction in electrical consumption and heat output. The savings don�t stop there; server hardware is only a piece of what you pay for. You need battery backups, network switch ports, backup software and media, remote reboot switches and KVM (keyboard video mouse) hardware, all sized for the number of servers you have. Larger organizations or those who can�t afford any downtime probably have their most critical servers mirrored somewhere else for immediate failover. On the flip side, smaller organizations might not be able to justify the costs of this type of infrastructure and have to tolerate more downtime or management inefficiencies than they�d like. By switching to virtualization, those mirroring their data center will also mirror their savings, and smaller organizations will have the opportunity to add this additional infrastructure while still saving money. You can also get rid of the extra KVM and remote reboot switches as that functionality is provided through the virtualization software�s management suite. VM backups and restores are incredibly fast and easy. You can take snapshots of your machines and restore them without the need for any additional backup software. More powerful backup suites are out there and will cost you, but are generally licensed per processor so you can use one copy for all the VMs you have on one physical server. Operational Savings Some organizations claim a 50 percent to 70 percent time reduction needed to manage their server environment after converting to virtualization. This percentage depends partially on the number of servers and their location relative to the IT staff, but mainly on the ease of deploying, manipulating and monitoring a virtual environment. For example, if you have 10 new servers that you need to install with the same OS, you would create just one virtual machine, install the OS and your base software, apply any updates and then clone it nine times. The cloning process is much faster than installing a full machine and you can save custom built templates to use for future machines. To test a patch or software upgrade, just clone the server or create a new one, apply the patch, and when you are done just throw away the new machine. Some VM settings can be changed on the fly without shutting a machine down: You can enable and disable the NIC (network interface card) or put it on a different VLAN, and you can manage the CDROM, floppy and serial ports using an image file on the network or your desktop�s own devices. Other settings, such as changing the amount of dedicated RAM or the number of virtual processors, only require a quick restart of the VM�no physical access, shock bracelets or screwdrivers needed. Upgrades are greatly simplified since you have fewer physical severs, and if you�ve already maxed out the server, you simply purchase an additional server and redistribute your VMs. If you use a SAN you can suspend and move a VM to another physical server manually in minutes or in seconds with additional software. Real-time performance statistics are available for all VMs from one interface and give you an indepth view of what resources each VM is using and how well optimized your physical server is. Security and Stability Virtualization actually helps build a more secure and stable environment. It is not uncommon for a server to have multiple purposes: file and print, Web and e-mail. Each application has its own set of security risks, patch needs and stability issues. Splitting these into separate virtual machines helps reduce your exposure if compromised, limits downtime when applying updates and prevents instability in one application from affecting other applications. Getting Started The top market share holders in the virtualization space all offer a free version of their hypervisor. They are easy to install and come with tools that will convert an existing physical machine into a VM on the fly. This gives you the ability to try them before you start converting your production machines. There are also type 2 hypervisors, which run on top of an existing operating system, that allow you to run VMs on your desktop or an existing server. Before converting your production environment, ensure you have a good understanding of the resource requirements of all your servers. This is one of the most common mistakes made when switching to virtualization. Make sure you aren�t putting machines that have the same peak usage times on a server that isn�t sized appropriately. There is also a tendency to max out the processors, but skimp on RAM. This is a bad idea�you�ll run out of RAM long before your processors are maxed out. More RAM means more VMs per physical server, so starting high allows you to add more VMs later without costly upgrades. Disk access can also be a bottleneck, so use only 15K RPM drives and create more than one RAID array to maximize your IO. Also, you should understand that even with the newest hypervisors there is still a layer between your VM and the server hardware so there will be a slight performance impact. In most cases this won�t be noticeable, but you should understand that it is a possibility and test your critical applications before going live with them. Lastly, make sure you have spare hardware and a solid backup plan as you are increasing your exposure by putting several servers on one physical device. If this one server goes down you will lose multiple applications, so make sure you can quickly fail over to another server. (There are type 1 and type 2 hypervisors � type 1 runs directly on the hardware with its own kernel � or on the bare metal. Type 2 hypervisors require an operating system already be installed, and the hypervisor runs on top of that. Type 2 hypervisors have more layers between the virtual machine and the actual physical hardware and are thus less efficient.)
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� Hospitality Upgrade, 2009. No reproduction or transmission without written permission. |
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Managing Editor Hospitality Upgrade magazine and the Hospitality Upgrade.com website http://www.hospitalityupgrade.com/ [email protected] |
