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As we mentioned in the beginning of this section, the key to fault tolerance is to not lose data and also not lose functionality. Or at least not lose functionality for an extended period of time even in the event of a disaster. So in this restoring your Server section, we will discuss identifying hardware replacements before they are needed, identifying our Hot and Cold sites, and then implementing the disaster recovery plan and learning from what's happened in the past. In the event that our equipment was to actually be damaged, we would need to replace that equipment. So most organizations identify sources that can replace equipment even in the event of an emergency. There are many different sources that provide this types of replacements. They can replace a servers and racks, memory, disk drives, CPUs, Network Interface Cards, cables - whatever it takes to get the system up and running again. And there are basically two different types of sites - hot sites and cold sites. A hot site has equipment standing by on hand. In the event that a company has a disaster, hot sites would have contracts with a company that says - if this happens, if there is an earthquake, if there is a flood, if there is a fire then we will have equipment standing by on hand for you. They have in depth disaster recovery capability, and it's usually very expensive to have these contracts with hot site companies. So only large organizations and/or organizations that absolutely must be up at any given time will provide for hot site capability. Cold sites on the other hand are just warehouses. It's a place to put old or damaged equipment, a warehouse environment type of situation, maybe there is some repair facility within it. But it's not as organized or intricate a design as a hot site. Cold sites are sometimes called depots, where damaged equipment goes to the depot - sometimes it's worked on, or sometimes it's just disposed of. What happens to the equipment and what we can salvage will determine how fast we can get up to speed. But, we also need to have a plan. And we can learn from things that have happened in the past to this organization or to other organizations like ours, and then build our plan and then learn from future occurrences. So a disaster recovery plan should include documentation, and we should work through the documentation then in the case of a disaster. In other words, we should be ready for whatever might happen, and then we can just work through the plan. It's probably not a good idea to start making a plan after we have had the disaster; we got other things on our mind at that point. We can make changes to the plan if necessary, but we should have a plan in place. And then we need to document what worked and what didn't work in recovering from this disaster, so that we can help our own organization as well as other organizations in the future. So this completes the formal training for Server+, and reviewing this material should help you to pass the test. But as I said in the beginning, I have included a special section with some tips that I use to take and pass Certification Tests. And I will cover these tips in our next chapter.