Is it really better to save backups to an external hard disk

If you plug in your external drive via USB and leave it connected, for all intents and purposes, it becomes an internal drive. The way you should use an external drive for backup purposes is to connect it, run your backup, disconnect, store in a safe place away from the computer. If your data is critical to you, you want to store your backup drive in another location (such as a safe deposit box in a bank).

If you do your backups to an internal drive or to a permanently attached external drive and your computer gets stolen, you lose all of your data as well. If your computer is destroyed by fire, flood, lightning, etc... you lose all of your data. Insurance can replace your computer, can it replace your data?

You may want to continue backing up to an internal drive on a daily basis but add regular backups to an external drive on a weekly basis and store that drive in another location. How often you backup depends on how much data you generate and how important the loss of any of the data would be. For instance, let's say you do your weekly backups to the external drive on Saturday. Then you work on your computer all week but the computer is stolen or destroyed on Friday evening along with your internal backup. The remotely saved backup would be a week old so you would lose the data for that week. Is the loss of a week's data acceptable? If not, then more frequent backups are required.

1. A backup saved to an external drive that is connected to the computer only when updating the backup is isolated from the sources of danger to your data on internal drives.

2. No, you are not safe!

3. Electrical shock (such as ElectroStatic Discharge, aka ESD), power surges and spikes, and a failing PSU (power supply) are not the only reasons for not keeping backups on internal drives. If a virus or other malware infects your computer, the chances are excellent that an internal backup drive will also be infected. Physical damage to the computer, such as dropping it, could damage or destroy all your HDDs. If your computer gets stolen, there goes your backups.

4. If you have an external drive connected to the computer by just a USB cable and it isn't powered up, it's unlikely that it will be damaged by a surge or spike from a lightning strike. However, if the external drive is connected to the power lines, it is very likely the drive will also be damaged, even if the drive is turned off.

Generally, your data isn't safe unless your data is stored in three locations, such as the original drive in the computer, a locally stored external backup drive (preferably not stored right by the computer), and an external drive stored offsite, such as in a locker or locked drawer somewhere other than where the computer (such as at work, a friend's house, or a safe deposit box at a bank if the computer is at home). Also, the backups must be connected to the computer only while actually updating a backup and the backups must be updated frequently.

I backup to 1 internal drive and 2 external drives (in alteration). The external drives are disconnected when not in use. Thus they are safe. The internal drive I use only for convenience.

I've never had any electronics fried due to a surge or spike, mostly because I use surge arrestors. I have read plenty of times where others have had it happen to them.

If a nearby power line takes a direct hit from lightning, no amount of surge protection will protect your electronics. The chances of that happening are very slim, however; not enough to worry over as long as you have insurance to replace the barbequed electronics and a good backup scheme to protect your data. What you do need to worry about is keeping your data properly backed up with your backups isolated from the computer. You are far more likely to lose data from malware, random HDD failure, disasters, theft, etc. than you are from surges or spikes.

Some people keep backups on internal drives for convenience—I save my boot drive images to my main data drive for that reason—which is fine as long as backups are also maintained off the computer. Since even backup drives can fail or something go pear shaped while updating a backup—I've had both happen—a second backup drive that never gets connected to the computer while the first backup drive is connected is also essential. I've had my bacon data saved by having a second backup.

pcwin said:

Thanks for all replies.

Did anyone ever experience lightning and power surge/spikes/power related problem killing internal hard disk? It seems like the chance is very little (I guess maybe lesser than 1%) as I never read about true experience before, all are written theory.

I haven't, but it depends on where you live and how much lightning activity occurs there. Where I live, we don't get many thunderstorms and the ones we get aren't very severe. I don't use any surge protection for my electronics and don't know of anyone that does.

However, there are many other things that could happen to your electronics or your internal hard disk that are more likely to happen so it's still important to have a good backup strategy.

Here I am simple ole me.

Lightning is unpredictable.
Computer power supplies are unpredictable.

Both can destroy anything in a computer but not always therefore unpredictable.

I have never had lighting problem. I have had a power supply years ago take everything in a PC out except the cheap ass case fans. Some how they lived through it.

What to make of all this.
Keep a copy or more of things that you want to protect out side your case and unhooked from your computer in any fashion.

Don't store your backup drives in anything metal that some how or some way lighting might take a liking to.

I have seen the results of lighting in a work friends house.

Some how lighting worked it way down a phone line through a surge protector. Which it melted.
Then blew up the computer, went through a wall and blew a hole the size of a softball in a old cast iron bathtub. From there the insurance people think it followed the pluming to ground.

Why the lighting didn't strike the lighting rods on this old farm house is unknown.

Unpredictable.

Why didn't the surge protection stop the surge is simple. They are not made or designed to stop lighting and I don't know what is.