Power Redundancy – SY0-601 CompTIA Security+ : 2.5

Maintaining a power source is an important part of any security strategy. In this video, you’ll learn about UPS systems, generators, dual-power supplies, and power distribution units.

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Perhaps the primary resource we need to be able to operate our computers, our laptops, and mobile devices is power. To be able to maintain power during times of brownouts or complete outages, we can use a UPS, or uninterruptible power supply. This is a device that has batteries inside. And if the power goes out, we use the battery power instead of using the primary power source. This is a temporary power source, because those batteries are only going to last for a certain amount of time. But if you’re only concerned about temporary outages, a UPS can be a very useful tool.

You’ll generally find three different kinds of uninterruptible power supplies. And they usually are a little more expensive as you get some more advanced features. One of the simplest and least expensive of the UPS is an offline or standby UPS. This is a UPS that is not normally enabled unless power is lost. If the UPS recognizes that the power source is gone, it will switch over to battery power. So there’s a short time frame between the time when power is lost and then power is made available from the UPS.

Another type of UPS is a line-interactive UPS. If the voltage is slowly diminishing on the line, the UPS can slowly ramp up the amount of power being provided by the batteries. So during brownouts or times when the voltage is not at optimal levels, the line-interactive UPS can fill in the differences for the power source.

The kind of UPS that’s probably the most complex and the most expensive is the online, or what is called the double conversion, UPS. This UPS is always online and always providing power to your devices. And if the power does go out, there’s no switching process, because you’re already on battery power.

There are many different kinds of devices that you can purchase. And there are different options available depending on the model. Some have an auto shutdown capability. So when power is lost, it can send a signal to your computer to automatically power it down safely so that no information is lost.

There are also many options for battery capacity so that if you lose power, you may be able to maintain uptime for an hour, two hours, or more. You can often choose a UPS that has a different number of outlets on the back of it. And many UPS devices will have phone line or cable modem suppression. So you can remove any type of voltages from those connections as well.

If you need power to be maintained over a longer time frame, then you might want to move up to a generator. A generator is a long-term power backup that can keep the power running for days or even weeks at a time. As long as you have fuel available to run the generator, you can maintain the power. These generators can often power an entire building, or at least a number of outlets inside of that building.

Often the outlets are marked to show that they will provide power during an outage. Once the power goes out, there’s usually a 10- or 15-second waiting period to see if the power happens to turn back on. And if it does not, the generator turns on and begins providing power to the building. During that 10 or 15 seconds, though, you will need some type of internal power in the building to make sure that all of your systems remain up and running, which is why you might combine both the UPS and the generator power to make sure that all of your computing systems stay active and available.

If you’ve ever connected a computer to the power source, then you’re probably familiar with connecting that power cable and turning on the computer. But what if there’s some type of hardware failure and the power supply itself fails? In that scenario, you might want to have a server that has multiple power supplies inside of it where you can plug in multiple power sources. And if you happen to lose one of those power supplies, the other power supply continues to provide power to that device.

These power supplies are designed so that each individual power supply can support the power for the entire system. This means if you plug in one of those power supplies, as we see in this picture, that single power supply can provide 100% of the power load for that server. If you plug in two separate power sources to both of those power supplies, then each power supply will be providing 50% of the load for that server.

This picture is in the middle of an installation where half of the power is being provided by one particular power distribution unit, and there will be a separate power distribution unit that handles the power for the other side of the power supplies. These power supplies are often hot-swappable as well. So if one of these was to fail, you can pull this power supply out, put a new one in-line and plug it in, all while the computer remains up and running.

A power distribution unit, or PDU, is usually a device that provides multiple power sources. This is a very simple PDU that has eight different power interfaces inside of it. It connects to an ethernet network. And each one of those interfaces can be controlled across the network. These PDUs also have monitoring capabilities. So they can report back if there are any type of power problems. And they can constantly monitor the power load across all of those interfaces on the PDU.