Backup Strategies: Using an external drive

There are many ways to backup your data nowadays.

Some of the popular ones are:

• Use an external hard disk and make copies on to it periodically
• Use a local network storage device or what is commonly known as a NAS box
• Use an online storage service such as Dropbox, Skydrive or Crashplan

Today I will talk about the external hard disk method and its advantages and disadvantages

Advantages

Cheap

The cost of a typical external hard drive is very cheap. A good Seagate 1 TB hard drive is available for about 90 USD. 1 TB should provide enough space to store your music, photos, documents and anything else that you can throw in there.

Portable

The aforementioned Seagate drive is very compact and can easily be carried around in a small bag without any problems. This allows your data to be easily available to you. However, the cost of this portability is exposure to environmental factors, not to mention the possibility of physical damage to the device in case of an accident.

Space

The amount of space you get here is huge. At a cost of 90 USD for 1 TB, you are getting around 11 GB per dollar for the rest of the life of the device. This is a very efficient way to store your data at the least cost.

Disadvantages

Colocation Risk

One of the things we use an external hard disk is to protect our data from any one of the many random things that can happen and cause you to lose your data. An external hard disk is susceptible to some if not all of these risks.

Eg: A natural disaster such as fire will not only destroy your primary hard drive but might also destroy your secondary hard drive if you didn't carry it out with you.

A power surge might destroy both your primary and secondary drives if they happen to be plugged in.

In fact, the only situation in which the external hard drive protects you from data loss is in the case of hard drive failure of your primary disk or laptop/desktop.

Physical Access Constraint

The data on your secondary hard drive is only available to you when the hard drive is with you. If you lose the hard drive or leave it at home, the data is obviously not available.

You have to remember to carry around the disk with you always.

Disk Failure

Disk Failure is a very real and possible scenario in many cases of data loss. The secondary hard drive is not protected from this outcome as it is nothing but another hard drive in its own case. The circumstances that caused the hard drive failure of your primary drive might cause the secondary to fail. Noted, the disk might have a chance of failing less due to the fact that its usage will not be as great as your primary hard drive. The risk however exists.

No Redundancy

The data on the hard drive is normally stored on a Filesystem (usually a Windows Filesystem). There can corrupted entries in the data caused due to bad sectors in the hard drive or due to corruption of data on the disk. This is usually avoided by the use of redundancy mechanisms such as RAID, where the data is spread over multiple disks, so that a corruption in one disk is corrected by data from another disk.

Note, that not all RAID configurations provide this kind of redundancy.

When should you use this?

The cost effectiveness of the external hard disk provides a good backup mechanism when cost is a concern. However, using the external hard disk as a backup mechanism where the hard drive is stored in a different location is a good way to mitigate some of the risks mentioned previously. A hard drive that is in a different location will not be easily accessible to you, however, it will not be affected by any events that cause your primary hard drive to fail.

Using an external hard drive combined with another backup mechanism would be my recommended approach. I will go into more details about that in a future article.