Gumbo and Security

I love gumbo and my wife and friends love the gumbo I make.
I have computers in my home office.
I am an Eagle Scout.

These three things, combined with an experience from college, make me have and test backups of my data and of my power.

First, the power. My office is at home. That’s probably not true for most of you though, but this applies to you too. You see, the electricity can go out anywhere. Some winters mine has gone out for over a day. I know others whose commercial power has been off for extended periods. Like most people I have a UPS (Uninterruptable Power Supply). Mine is big, though. It handles my office PCs, the office lights, the well, the refrigerator and the freezer. That way if the power is off I can still have some water and eat. There is usually gumbo (or ingredients for it) in the freezer.

The batteries for my UPS are large lead-acid batteries. They require the addition of water now and then. I could have purchased ones that didn’t, but they cost too much at the time. Anyway, my wife “feeds” the batteries every so often. I test them, too.  That’s important.  You see, batteries don’t last forever. Neither wet led-acid batteries nor sealed batteries have an infinite life span.

A friend who installed small UPSs in businesses often tells me of sealed lead-acid batteries that puffed up and died. They had to be replaces. Sadly, most customers did not find out until they needed the UPS and there wasn’t any more power left in the batteries.

So I test. If the power has been on for a long time, I flip a switch and batteries run the office for a while. I generally only do it for a few hours, but some people say I should do it for longer to really “cycle” the batteries. The company who makes the batteries doesn’t recommend that, so I don’t feel the need.

Some years ago, when I was in college, I worked for a company installing telephone systems for businesses. One installation had a large diesel generator. When the power went on the generator was supposed to kick in and supply power. One problem, however, was that when the generator started, it provided a fairly large power spike. That was unhealthy for our electronic phone system – it caused all the fuses to blow! I solved the problem by installing a relay so a human could connect the generator to the phone system after the generator had been running for a minute or two.  That system was tested frequently, too.

When I was in college we had a tape system to back up a computer. I made backups every week (pretty normal back then) and I tested them to be sure the tape could be read. At one point the tape drive needed to be serviced and the people maintaining it re-aligned the heads. That is a process where the unit the reads and writes the data is aligned with the tape in a pre-determined way. It seems our drive was out of alignment. It was a disaster!

While I kept backing up and testing backups, I had no idea that the tape drive could no longer read older tapes written with mis-aligned heads. All the old backups were useless. My testing of each backup was still valuable, but all the old data was lost.

Both backup of data and power backup are issues of Availability. Both require testing. It is important to test whether you can actually restore your system(s) from backup,  but that is another post. The point is to Be Prepared, something I learned in Boy Scouts. Test the UPS whether it’s a little one at home or a big generator at an enterprise data center. How will you know it will work in a real power failure if you don’t test it?

Jimmy Buffett says he “will play for gumbo.” As long as my UPS keeps working, and I will keep testing it to ensure that it does, I’ll have some gumbo around and hopefully Jimmy will come by and play. In the mean time, I’ll be teaching Learning Tree’s course 468, System and Network Security: A Comprehensive Introduction, where you can learn more about Availability including backups and testing.

John McDermott

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