Benefits and Drawbacks of Virtualization

February 21, 2007 at 9:20 am | Posted in Technical | Leave a comment

To virtualize or not to virtualize? That is the question. In short, every organization’s needs are unique, and there’s no ‘canned’ answer that will fit everyone. Here are some questions to ask as you’re making this decision.

1.  How many ‘boxes’ do you have right now per staff member, and how many do you think you’ll have in 2 years? 4? Will your staffing level be able to keep up with the growth of your server farm?

2. What is your IT funding model? With virtualized servers you have the option to bill back actual computer usage to the department who used it, since you can identify each department’s data footprint and CPU usage. If your budget is still divvied up over departmental lines based upon physical boxes, you may need to make some changes in the finance office first.

3. What is the cost of the physical space required for your servers? If you are in a crowded environment and space is at a premium, you may wish to elevate virtualization to a higher priority. If you’re in a giant warehouse with ample space to spare, this may not be a concern for you at all.

4. What is your company’s overall ecological footprint, and is it important to you to be eco-friendly? If you place a high priority on reducing your power consumption, that may be a vote for virtualization, since your systems and cooling devices will suck up much less power than a box-based architecture. This will also save you money on your power bill each month.

5. What is the size of your network? If you are running a small network of less than 10 servers, virtualization may not give you a good return on your investment. The “sweet spot” for virtualization starts somewhere between 15 and 30 servers, and generally occurs in companies with 100-5000 employees. When companies are much larger than that, they will tend to fragment their IT services into different physical areas, and usually a mix of virtualized and non-virtualized approaches is best.

6. What kind of long-term savings are you hoping to achieve? In truth, virtualization may not help with your software budget at all. Hardware, though, can make a huge impact on your bottom line. Everything depends on what sorts of hardware you were buying in the past, but most companies who virtualize have projected savings of 40-70% on hardware purchases in their budgets following virtualization.  

7. This won’t reduce your staffing budget. You likely will not be able to reduce your IT staff due to virtualization. The level of responsibility they have in a virtualized environment is about the same as with a server farm performing the same computing workload.

8. Is up-time important to you? Availability of virtualized systems is the highest of any type of server architecture. If you place a high priority on 24/7/365 up-time, that’s a big “yes” vote to virtualize.

9. What is the cost and headache associated with your current disaster recovery plan? Virtualization can alleviate a lot of this concern.

10. What is your vision for IT? This seems to be an abstract concept, but your overall long-term view of what you provide for your organization really does matter to your strategy. If  you view technology as a service you provide for the people in your organization, virtualization can be a great tool toward designing those services and separating them ideologically from hunks of hardware on a rack. If your goal is to impress visitors with the size and splendor of your astonishing 30 racks of servers, virtualization is not for you.

Some drawbacks of virtualization you’ll need to be prepared to handle:

1. Your software licensing might get complicated. Though more software vendors are adjusting their approach, historically licenses have not allowed for the way virtualized servers utilize their processors. One example is Oracle, which sells licenses on a per-processor basis. If your virtualized server has 4 servers, and you plan to use just one of them with Oracle, Oracle is still going to charge you for a four-processor license.

2. You have to very carefully manage your system resources when you virtualize multiple servers into one,  because all of those will share the same I/O. You’ll need to make sure you have plenty of machine to handle the demands of your users, or you may run into bottlenecks.   


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