May 2005

Your hard drive contains a good piece of your life. Pictures, music, documents, email, software. If it all just disappeared tomorrow, how would you recover? The average computer is happily running Windows 98 and is approaching the ripe old age of 5 or 6 (or 35 in dog years), Windows XP is approaching age 4 (a teenager in PC years, just starting to get mature) and I am here to tell you - It is not a matter of IF but WHEN you will lose your precious data stored on hard drive.

What if a virus or some poorly written program deliberately or accidentally wipes out your data files or file structure. What would you do then? What if your PC is damanged or stolen? What then? Or if the harddrive just decides to take a permanent sleep one fine day. Yikes. The scary part is I see it happening all the time in my line of work.

While hard drives are now more reliable than ever, a regular program of backing up critical data and storing offsite is prudent and always recommended. The salesman selling us a new hard drive will point to numbers like the MTBF to close the sale. Just what is MTBF? It is the hard drive manufacturers estimate of when you are really going to NEED that last good backup. It stands for Mean Time Between Failure. An average drive has a MTBF rating of 300,000 hours of operation. But wait, you say. If most hard drives have MTBF ratings like 300,000 hours (about 34 years), why worry? My response is, If the drive is supposed to be good for years to come, why do why do we experience any disk crashes at all? Why do so many systems end up in my shop with no working hard drive left inside the case? In other words, face reality, those MTBF ratings are seriously overrated. The fact that MTBF ratings exist at all, however, underscores the dark fact that every disk drive will eventually fail if run long and hard enough.

MTBF Calculations Unveiled

"Mean Time Between Failures (MTBF) is calculated by taking a batch of equipment and seeing how many units fail during a given period of time. If, for example, you took 1,000 hard drives, ran them for 100 hours and had one drive fail, that would give an MTBF of 100,000 hours (1,000 units x 100 hours = 100,000 MTBF hours). If you had one failure in 200 hours, it would yield an MTBF of 200,000 (1000 drives x 200 hours = 200,000 MTBF hours); one failure in 300 hours would give an MTBF of 300,000 (1,000 drives x 300 hours = 300,000 MTBF hours) and so on."

Predicting Failures Based on MTBF:

"Using an MTBF of 100,000 for example: If you bought 1,000 of the drives you could then expect one drive to fail every 100 hours (100,000 MTBF hours divided by 1,000 hard drives = 100 hours). If you bought 100 drives one could be expected to fail every 1,000 hours (100,000 MTBF divided by 100 drives = 1000 hours); with 200 drives, one would fail every 500 hours (100,000 MTBF hours divided by 200 units = 500 hours); with 300 drives one would fail every 333.3 hours (100,000 MTBF hours divided by 300 drives = 333.3 hours).

"This doesn’t mean that you can take one hard drive and run it for 100,000 hours. The MTBF figures only apply to the first year of operation, and there are less than 9000 hours in a year. But the MTBF rating does provide a comparative quality rating. If for example one hard drive had a rating of 100,000 hours and another was rated at 200,000 hours, it doesn’t mean that the second one would last twice as long, but that the second one would fail half as often in the first year.

Source: http://www.execsoft.co.uk/html/news/focus/focus7-3.htm

So, MTBF only gives us a crude idea of whether your hard drive will experience a single candle on the birthday cake. What we need to consider is the RTBF or Real Time Between Failure. In this (my own) rating system, an I-Doubt-It factor of 10 is applied, resulting in the assertion that the average hard drive is going to fail at an age of about 3.4 years, or just before you have to finish an critically important job on your computer. Some drives fail a little sooner and some a little later, but sooner or later they will fail. Then you will be calling someone like me up to verify the time of death or to perform the last rites or to attempt a resurrection.

Real backup, like repentance, is more important today than ever. Hard disk capacities continue to grow, as do the amount and importance of the data stored on them. At a minimum, real backup means consistent backups over multiple pieces of media, with at least one copy kept off-site. The home user can afford to be less diligent, but the file you overlook is usually the one you will need and the precaution you fail to take often costs you in time and real money down the road. A sound strategy and a consistent schedule is what is needed. Here's my recommendation for most users:

Install an extra removable hard drive or DVD or CD-Burner to burn disks for your archive. Floppy disks just don't cut it anymore. Save all important data that you wish to backup on a regular basis into a single data folder e.g. into your 'My Documents' or equivalent file. Only keep the important data here.

This method provides regular data backups to protect you against minor calamities, and a complete backup to protect against major ones.

So, now you have been warned. When your end-time arrives, may the peace of the righteous backer-upper be yours - along with that desperately needed backup file. Peace!

May 2005

The End is Coming .. Backup Today!