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Beware of Zombie Servers

According to studies, there are approximately 3.6 million zombie servers in the United States and over 10 million of them worldwide. These zombie servers are consuming the amount of power that can otherwise be used to power over eight large power plants.

But, what are these zombie servers?

Zombie servers are dormant, “comatose”, or “undead” servers in a data center that simply sit and consume both physical space and power without running any compute load. In other words, they are running but have no external communication or visibility. Zombie servers are formed when user-requested applications are not utilized (or utilized less than 6%), or when the applications and services they housed have become redundant or obsolete and, therefore, have been replaced.

Like the fictional “undead” beings, zombie servers slowly but surely suck up and deplete your data center’s resources. Zombie servers make up for about 30% of servers in a data center, eating up about one-third of its capital. They contribute to one of the biggest power efficiency problems faced by data centers. Since zombie servers often go undetected for long periods of time, they are not patched or maintained and, therefore, pose a great security risk as well.

What can you do to get rid of them?

When it comes to solving the problem, there are only two ways to go about it. In both ways, the first step is to identify the zombies in your data center. The second step is to either wake them up (put them to good use) or shut them down (unplug them). If there are many low-utilization servers, they can also be combined into one virtual server.

Often, the biggest challenge is faced in identifying zombie servers. It is estimated that a large data center may have hundreds of them and be oblivious about their presence.

Here are some ways to identify and prevent zombies from lurking in your data center:

Undertake Asset/Facilities management

Only through proper management of assets and facilities as well as periodic inventorying of each server can those that are no longer needed be identified. Take into account the physical location of all servers, make note of how each of them contributes to the operation of the center, track changes made to applications on these servers.

Use monitoring tools

A Data Center Infrastructure Management (DCIM) tool can help you monitor a range of parameters within your data center – from overall power usage to branch-level and individual circuits and rack-level power strips. Using tools like this can help you spot energy drainers easily and gather data on server utilization.

Set up procedures to avoid zombification

Take a close look at your existing procedures – especially those with regard to bringing in new assets/servers without fully utilizing existing ones. Make sure every new acquisition is justified and keep track of the average lifecycle of each server you bring in to your data center. Use a thorough documentation system that will clearly state the role of each server. Consider annual updates and audits, which will help you purge any traces of zombification. 

Need help with zombie hunting in your data center? At Hardy Racks, we offer expert data center consultation and efficiency assessment services. Get in touch with us for more information!


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