Data Centers

Do More with Less: Is less more when it comes to server consolidation?

The benefits of server consolidation


By Larry Seltzer

Some old ideas are making their way back into technology hipdom. You may have seen IBM's TV ad, "The Heist," pushing its zSeries mainframes running Linux. It's a great ad—much better than those dreadful basketball ads. The point the ad makes is that consolidating many servers into one can save you "a bundle."This ad is part of a general campaign to promote Linux, but I'm more interested in the idea of consolidation than the actual operating system being used.

Big questions for big servers
Server sprawl is a legitimate concern for a number of reasons, and you can make a cost argument for a smaller number of more powerful servers independent of the hardware cost: They can save money in terms of power, service agreements, and even the cost of physical space.

However, there is the related question of performance growth in your servers. Does it make better sense to have a larger number of cheap, commodity servers or a smaller number of higher-end, more powerful servers? In the most abstract sense, there are great arguments on both sides, and many companies, including both IBM and Microsoft, sell solutions in both spaces. The real answer is that it depends on your situation and your applications, and only someone familiar with your particulars can make an intelligent decision for you.

How do we end up getting server sprawl? Companies will buy and organize servers on an organizational basis. There will be marketing servers, engineering servers, accounting servers, and so on. Plus, these servers have gotten cheap.

If you want to be sophisticated about it, you can combine many low-end servers into a cluster that solves large problems and can perform more work in parallel. It's not uncommon, for example, to cluster several Intel-architecture or Sun servers together running a single database application, usually partitioning access to the physical database. A query for a record beginning with the letter A may normally go to one system, while a query beginning with S goes to another.

There's a lot to say for having a large number of smaller servers, my favorite argument being that it gives you redundancy. If you plan correctly, should there be some problem with one of the servers, you should be able to find another with some free capacity and transfer. The hardware is pure commodity stuff, and you can switch vendors at will, for the most part.

But then one day, you wake up and you've got so many servers that some vice president starts complaining about your air conditioning and electric bills. And the high-end servers are also coming down in price, and the quality of their components, so I'm told, tends to be higher, so you're less likely to have to deal with hardware failures. (Good thing, since less redundancy means you'll be more reliant on each server.)

Examining the benefits
I can see that there may be cost savings in this regard if you were able to take scores of servers and replace them with a few, but I'm not as clear on how there are any large "management" savings. Unless you also completely reorganize your IT infrastructure, you're still going to have all the same management tasks to perform. It's not likely that simply having fewer server systems will mean you need fewer administrators, because most of the same administrative work will remain. And not all administrators have the same skills. Database administration and file/print administration are very different, for example.

Backup is one task that, in most ways, is facilitated by consolidation. It's just easier to back up a smaller number of servers. Of course, these servers will have relatively large storage sets, so you will likely need to acquire new backup hardware as part of your consolidation scheme.

The IBM consolidation ads could use a little more detail in their explanation, by the way. Even though the servers are running Linux (actually, they run multiple virtual instances of Linux), they are essentially mainframes and a tough sell to any IT shop that has no existing mainframe expertise.

In large corporations where mainframes are common and core to the mission, one of these zSeries fridges can be a great way to take projects out of a "startup" mode and put them into a more mature, reliable environment. Don't get the idea that a standard Microsoft shop would be well served by one of these. Some of the same stuff is going on in Windows-land, though, and for all the same reasons. It could easily pay to consolidate lower-end database servers from different departments onto one big monster box that still had room to grow.

Larry Seltzer has written computer articles since 1983. He has worked for software companies and IT departments and has managed test labs at National Software Testing Labs, PC Week, and PC Magazine.


Is server consolidation appealing for your own company?
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