he End is Coming .. Backup Today!
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 4 (or 28 in dog years), and I am here to tell
you - It is not a matter of if but when you will lose data from your hard
drive.
While hard drives are now more reliable than ever, a regular program
of backing up critical data is prudent and always recommended. The salesman
selling us a new hard drive will point to numbers like the MTBF to close the
sale. 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 disks
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, MTBF ratings are seriously
overrated. The fact that MTBF ratings exist at all, however, underscores the
fact that every disk drive will eventually fail if run long enough.
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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
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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.
What to do? Backup ye sinners, Backup!
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 CD-Burner to
burn CD's 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 file. Only keep the important
data here.
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Weekly or Monthly: Do a full backup of everything in your
system onto the removable hard drive, and take that backup offsite.
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Daily or Weekly: Make a backups of your data folder onto a
CD or a removable drive.
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!
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