Not Storing Backups on an Internal HDD

[M and D]

I've often read, in these boards and elsewhere, that one of the reasons for not storing backups on your computer's internal hard drive - even a second internal hard drive - is because 'it's not a question of if your hard drive will fail, but when.'

I don't quite understand the logic behind this, and here's why:

1) If I store my backups on my external hard drive...well, that's also a hard drive. And if I store my backups on a network...well, that too is a hard drive.

2) I've been reading for years that hard drives are getting more and more reliable, to the point where the chances of a drive failing on its own are very, very small. And from what I've read, hard drives are a much more reliable (and longer lasting) medium than are CDs or DVDs.

To my understanding, the reason for not storing backups on the same computer is to safeguard against the relatively more likely possibility that some external cause (viruses, theft, lightening strike, etc.) will make the computer unusable. Is this correct?

Daddy

 

[Kerry Brown]

I've often read, in these boards and elsewhere, that one of the
reasons for not storing backups on your computer's internal hard
drive - even a second internal hard drive - is because 'it's not a
question of if your hard drive will fail, but when.'

I don't quite understand the logic behind this, and here's why:

1) If I store my backups on my external hard drive...well, that's
also a hard drive. And if I store my backups on a network...well,
that too is a hard drive.

2) I've been reading for years that hard drives are getting more and
more reliable, to the point where the chances of a drive failing on
its own are very, very small. And from what I've read, hard drives
are a much more reliable (and longer lasting) medium than are CDs or
DVDs.

To my understanding, the reason for not storing backups on the same
computer is to safeguard against the relatively more likely
possibility that some external cause (viruses, theft, lightening
strike, etc.) will make the computer unusable. Is this correct?

Daddy

What about the following scenarios? Your power supply blows and sends 12
volts to the five volt lines. Your hard drive controller develops a problem
and corrupts the data on both hard drives. Your place of residence burns
down, floods, is hit by a tornado etc. Your computer is stolen. A
friend/lover/acquaintance gets mad at you and erases whatever they can find
on the computer. You reinstall Windows and somehow both drives get
formatted. I have seen all of these scenarios. If you only have one method
for backing up it should be stored on something that can be stored somewhere
other than near the computer.

 

[Ken Blake, MVP]

I've often read, in these boards and elsewhere, that one of the
reasons for not storing backups on your computer's internal hard
drive - even a second internal hard drive - is because 'it's not a
question of if your hard drive will fail, but when.'

No, that's not a reason for where you put your backups, that's a reason for
making sure you *do* backups regularly.

I don't quite understand the logic behind this, and here's why:

1) If I store my backups on my external hard drive...well, that's
also a hard drive. And if I store my backups on a network...well,
that too is a hard drive.

Yes, but if the likelihood of one hard drive failing is x, the likelihood of
both hard drives, not in the same machine, failing simultaneously is X^2.
And since x is a number much smaller than 1, x^2 is a tiny nuimber indeed.

You can never reduce the risk to zero, but you can reduce it a number small
enough that most of don't have to worry about it.

2) I've been reading for years that hard drives are getting more and
more reliable, to the point where the chances of a drive failing on
its own are very, very small.

No, not true. The chances of a drive failing on its own are nort small at
all--just the opposite. It's *certain* that every drive will fail on its
own. A hard drive is a mechanical device. *All* mechanical drives have
wear-associated problems, and they all fail sooner or later.

The only question is *when* it will fail. True, drives are more reliable
than they used to be, and they do typically last longer. Nevertheless sooner
or later they will fail. Although average time to failure is pretty long
these days, averages don't count when protecting your data; some drives fail
sooner and some take longer to fail. You need to protect yourself against
the possibility of yours failing sooner. If your data is important to you,
trusting a drive to not fail, and not backing it up, is foolhardy.

Moreover even if the drive itself doesn't fail, user error, virus attacks,
severe power glitches, nearby lightning strikes, etc., can cause the loss of
your data. That's why you need to proretect yourself with backups.

And from what I've read, hard drives
are a much more reliable (and longer lasting) medium than are CDs or
DVDs.

Nope, that's simply not true. But even if it were true, it's irrelevant. The
chances of an original and a backup failing simultaneously are always much
smaller than either failing alone, and that's why you back up.

To my understanding, the reason for not storing backups on the same
computer is to safeguard against the relatively more likely
possibility that some external cause (viruses, theft, lightening
strike, etc.) will make the computer unusable. Is this correct?

Yes, but it's not a question of making the computer unusable, it's a
question of having the drive disappear--either physically (via theft, fire,
etc.) or just its contents lost (virus attack, lihghtning, etc.).

 

[M and D]

Thanks Kerry. I was kind of hoping you would answer my question.

So what you're saying, basically, is that I had it right: The reason for prefering an external location is not because hard drives eventually fail, but because a computer can get damaged, lost, stolen, etc. and in that event I am SOL if that's where I keep my backups.

Daddy

 

[M and D]

Thanks, Ken. I'm all set now.

Daddy

No, that's not a reason for where you put your backups, that's a reason for
making sure you *do* backups regularly.




Yes, but if the likelihood of one hard drive failing is x, the likelihood of
both hard drives, not in the same machine, failing simultaneously is X^2.
And since x is a number much smaller than 1, x^2 is a tiny nuimber indeed.

You can never reduce the risk to zero, but you can reduce it a number small
enough that most of don't have to worry about it.




No, not true. The chances of a drive failing on its own are nort small at
all--just the opposite. It's *certain* that every drive will fail on its
own. A hard drive is a mechanical device. *All* mechanical drives have
wear-associated problems, and they all fail sooner or later.

The only question is *when* it will fail. True, drives are more reliable
than they used to be, and they do typically last longer. Nevertheless sooner
or later they will fail. Although average time to failure is pretty long
these days, averages don't count when protecting your data; some drives fail
sooner and some take longer to fail. You need to protect yourself against
the possibility of yours failing sooner. If your data is important to you,
trusting a drive to not fail, and not backing it up, is foolhardy.

Moreover even if the drive itself doesn't fail, user error, virus attacks,
severe power glitches, nearby lightning strikes, etc., can cause the loss of
your data. That's why you need to proretect yourself with backups.




Nope, that's simply not true. But even if it were true, it's irrelevant. The
chances of an original and a backup failing simultaneously are always much
smaller than either failing alone, and that's why you back up.




Yes, but it's not a question of making the computer unusable, it's a
question of having the drive disappear--either physically (via theft, fire,
etc.) or just its contents lost (virus attack, lihghtning, etc.).

 

[Kerry Brown]

Thanks Kerry. I was kind of hoping you would answer my question.

So what you're saying, basically, is that I had it right: The reason
for prefering an external location is not because hard drives
eventually fail, but because a computer can get damaged, lost,
stolen, etc. and in that event I am SOL if that's where I keep my
backups.

You're welcome. That's exactly it.

 

[Ken Blake, MVP]

Thanks, Ken. I'm all set now.

You're welcome. Glad to help.

 

[Mike Hall, MS-MVP]

While it is convenient to store stuff on a second or external drive, the
very fact that drives are mechanical devices makes them a bad place to store
backups..

Backups should be made to media that can be removed from the machine
directly after the process has been completed, and then stored in a place
free of static, magnetic fields and dampness.. anything other than this is
just a copy..

An external drive can be used as a backup device as long as it is powered
down and removed from the system after the backup process has completed..
just like as above.. any other scenario, and the external drive is just one
more storage area..

--
Mike Hall
MS-MVP Windows Shell/User


I've often read, in these boards and elsewhere, that one of the reasons for
not storing backups on your computer's internal hard drive - even a second
internal hard drive - is because 'it's not a question of if your hard drive
will fail, but when.'

I don't quite understand the logic behind this, and here's why:

1) If I store my backups on my external hard drive...well, that's also a
hard drive. And if I store my backups on a network...well, that too is a
hard drive.

2) I've been reading for years that hard drives are getting more and more
reliable, to the point where the chances of a drive failing on its own are
very, very small. And from what I've read, hard drives are a much more
reliable (and longer lasting) medium than are CDs or DVDs.

To my understanding, the reason for not storing backups on the same computer
is to safeguard against the relatively more likely possibility that some
external cause (viruses, theft, lightening strike, etc.) will make the
computer unusable. Is this correct?

Daddy