How data gets lost

Summary:Our perception of risk and the reality of risk are often two different things. For example, are computer viruses or system glitches more likely to hose your data?

Our perception of risk and the reality of risk are often two different things. For example, are computer viruses or system glitches more likely to hose your data? While viruses get bad press for poor system performance, they aren't very likely to damage your data. Your system, on the other hand . . . .

This is data loss week at Storage Bits. I'll be talking about causes of data loss in some detail, starting today with the general factors and then drilling down into the major cause of data loss problems at the device and system levels.

Hoping for a silver bullet? There isn't one. Backing up your data regularly, either to a local hard drive or to an on-line service such as Carbonite or Mozy is your best bet. I will give you some concrete tips on limiting the damage in the one area you can control: yourself.

There is hope, however, that our systems will start treating our data a lot better than they do today. I'll cover that later this week.

What are the causes of data loss? I had a nice talk with the folks at Kroll Ontrack, the worlds largest data recovery firm. They have some interesting statistics on what actually causes data loss.

Cause of data loss Perception Reality
Hardware or system problem 78% 56%
Human error 11% 26%
Software corruption or problem 7% 9%
Computer viruses 2% 4%
Disaster 1-2% 1-2%
The numbers don't add up due to rounding errors.

Disk and system problems What is interesting here is that Ontrack's data suggests that we are too quick to blame our systems and not quick enough to blame ourselves. Their experience is that human error is a bigger piece of data loss than we'd like to admit. More on that below.

In general, there is little you can do about hardware or software problems. I use a battery backup unit with a surge protector to keep power clean and steady and maybe that helps.

My major strategy is to backup every day to a local disk. And I backup important files to an online service as well. As long as I've got a credit card to buy another system I can be on line in a couple of hours. And yes, I keep that password with me.

Why do I do both? Because recovery from a local disk is hundreds of times faster than downloading gigabytes over the net. But if a catastrophe happened, at least I still have access to critical data. I also keep a second machine - a notebook - for backup as well.

Panic is a factor in data loss Human error is a major problem in data loss. That shouldn't be a surprise: human error is a major factor in everything.

But there are some common things that people do that make data loss situations worse. When you suspect data loss, follow these simple steps;

  • Take a deep breath and stop! Panic is a common reaction, and people do really stupid things. Experienced admins will pull the wrong drive from a RAID array or reformat a drive, destroying all their information. Acting without thinking is dangerous to your data. Stop stressing about the loss and don't do anything to the disk. Better yet, stop using the computer until you have a plan of attack.
  • If your disk is making weird noises, normal file recovery software isn't going to work. I've had luck with performing a backup right away after hearing odd noises, but that is a matter of luck.
  • If the drive is still spinning and you can't find your data download a data recovery utility onto another computer. Google for "free data recovery software" for some options, including one from Ontrack. The important thing is to download them onto another drive, either on another computer, or onto a USB thumb drive or hard disk. If you don't you could be overwriting the data you are trying to save. It is good practice to save the recovered data to another disk.

If you have some tech moxie you might want to look at free data recovery programs such as NTFS Reader and PC Inspector. Neither is for newbies, so if you don't have a high degree of confidence in your PC ability, get a more knowledgeable friend to help.

If your drive is making grinding noises or has stopped completely, your data can still be recovered, but it will cost you in time and money. Google "disk data recovery" or check the back pages of your favorite PC mag for disk recovery companies.

The Storage Bits take Disk drive life may be a matter of luck, but data loss isn't. You can dramatically improve your odds by backing up your data on a regular basis to a USB or Firewire hard drive. For those whose livelihoods rely on computers, off-site backup is also a good idea, as is a backup computer.

Next: There are 50 ways to lose your data: a catalogue of disk woes.

Comments welcome. I'll update the post if I see a good one.

Topics: Data Centers, Data Management, Hardware

About

Harris has been working with computers for over 35 years and selling and marketing data storage for over 30 in companies large and small. He introduced a couple of multi-billion dollar storage products (DLT, the first Fibre Channel array) to market, as well as a many smaller ones. Earlier he spent 10 years marketing servers and networks.... Full Bio

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