In another thread, the discussion of where to store backup data came up. Using an internal disk drive was mentioned as was the idea that using an external drive or location would be safer. To continue:
the chances of two disks destructing at the same time are very small indeed.
Agreed. Use of an internal hard drive for backing up the primary drive is quite safe. If the primary drive fails ("destructs") due to wear and tear, poor manufacture, design flaws, or any other situation that is independent of outside forces, chances are extremely good that the backup drive will still be working. There is an interesting twist to this idea, though. When creating a RAID 1 (mirror) array, using identical drives is recommended. However, using two drives from the same lot, for example with sequential serial numbers, dramatically increases the (admittedly small) chance of a two drive failure. Especially since in a mirror, both drives will have the same power-on hours (POH).
Whats blunt force trauma-a hippo falling on it?
Maybe if you work in a zoo! Any sudden hard impact that can crash the heads of both drives is what I was getting at. If there is a word or phrase for that, I don't know it. Some folks keep a minitower on a desk and if it were to fall, that kind of physical shock might damage the drive heads, especially if they are not parked. A system could be accidentally kicked or hit by a swinging door or what have you. A laptop (we're imagining a 2-drive laptop here) could be dropped, and so on. These accidents do happen.
Its like insurance-if you are a belt and braces type, you no doubt will insure against a giraffe falling from the sky and injuring you.!
Yes, that illustrates an important point. There are plenty of scenarios that are possible, but most of them are improbable. We only want to deal with the possible that is probable or, better yet, known to happen.
Can't see any logic whatsoever to your strange statement that "The farther away the backup data is, the safer it is".
The key word is "safer", meaning more safe not perfectly safe. Moving the backup drive farther away from the primary reduces the chance of the possible, probable from happening to both drives. The physical damage was discussed above -- a shock to the case can potentially kill all internal drives, primary and backup. A lightning strike, even on a surge protected system, can burn out all the internal hard drives. A system with poor or no surge protection can be killed by power spikes, voltage spikes, and other irregularities. A beverage spill that gets in the case can cause a short-circuit and burn out all the internal hardware.
Moving the backup drive to an external case makes it safe*er*. Physical damage, power surges, and beverage spills can happen to the case holding the primary drive but the backup drive might be spared. Of course, the chances of the backup drive being spared is better if it is disconnected from the primary and the AC power. In a sense, this can be seen as "further away" -- so far that the signal and power cables won't reach -- and saf*er* still than the external that is always connected.
Its actually worse because the connections aren't as efficient as the internal ones,certainly with USB and in my case- had problems downloading and restoring with it. Therefore the dangers of a corrupted restore are greater.
Efficiency, or speed, are not important when the goal is to prevent data loss. What matters most is the reliability of the data. I don't understand the concept of data corruption being more likely on an external drive. Data transfers, whether internal or external, are parity checked and check-summed. No matter where it is written, the integrity of a backup archive should *always* be verified. Every backup system I have used has a verify feature. What problem did you have that makes you say this?
It still is going to be stolen (unless you take it with you ),burn in case of fire and if connected to the computer,be damaged if the other disks are going to be damaged.
Correct! These are cases where the backup (external) is still too close to the primary. But, disconnect the backup drive and store it in a closet, as whs says, and it will be safe*er*. Now it is, perhaps, less likely to be stolen since the primary PC, monitor, DVD player, etc. are all sitting out in the open and are easy to steal quickly without the thieves needing to search in closets. (Col, I'm thinking of you!) It's also possible that a fire could burn up the room where the PC is, but be put out before the room with the backup drive is burned up.
You are saying that the long accepted practice of a spare internal disk for backups is wrong.
I said no such thing, but please quote the relevant text if I did. I only said "be careful" and an external backup or off-site backup is "safer". An off-site backup means the entire house containing the primary drive can burn to the ground -- including whs's closet -- and the data will still be safe. It is, of course, up to the individual what steps they wish to take and I just want people to have all the information so they can make informed decisions.
Despite all that I have said on this topic, though it may sound preachy or pedantic, I don't have an off-site backup and I often forget to disconnect my backup drive. I know that my data could be safer, but these are the decisions that I have made.