Part of passing the Network+ exam and being an outstanding network administrator is being prepared for disaster. Sometimes that's a disaster on a relatively small scale, such as a drive failure. If you're running data backups on a regular basis (and you are, aren't you?), you're prepared for that issue.

What is your network's disaster recovery plan from a true disaster, either natural or man-made? What if the entire building your servers are in disappeared tonight? What is your plan if that happens? In today's world, that's not a rhetorical question. Disaster recovery is taken to the next level by preparing a cold site, warm site, or hot site at another physical location.

A hot site is the highest level of disaster preparedness. Hot sites are maintained by commercial companies for their customers, and these sites include everything from the office space itself all the way through telephone and computer equipment. The servers at the hot site will be mirrors of the servers at the primary location. Basically, your staff walks in and gets right to work.

Hot sites are very expensive to maintain. An alternative is a cold site. Cold sites will have the physical devices necessary to get up and running again, but they're not configured or mirrored from the primary site. This is much cheaper than maintaining a hot site, but obviously a lot of work needs to be done before work can continue after a disaster, and this is time many corporations, government offices, and public utility companies cannot spare in such a situation.

There is a middle ground, the appropriately named warm site. Warm sites are going to have all the physical equipment needed along with some of the servers configured and maintained. Disaster recovery using a warm site will still take longer than if a hot site were maintained, but basic communications are back in place much more quickly than if a cold site were used. The "mission critical" servers will be ready to go, but secondary servers will need to be brought up to date through data restores from backups.

You have to know about these sites to pass the CompTIA Network+ certification exam, but the stakes are much higher than that. If you're not the person in charge of network disaster recovery, find out who is and ask if any of these sites are being kept by your company. The better informed you are now, the better you'll be ready to get to work at such a crucial time.