Our Data, Our Selves: A Guest Post & Whitepaper on Data Backup

Guest Post & Whitepaper By : Aryeh Goretsky, MVP, ZCSE

While personal computers range in cost from a few hundred dollars for a basic system to enthusiasts’ rigs costing thousands of dollars (or more), a computer is a physical object, and it can be replaced.  What really makes your computer valuable is what’s unique about it, and that actually is your data.

While you can always purchase a replacement computer, you’re not too likely to find one at the local computer store that comes pre-installed with your business records, family multimedia (pictures, audio and video recordings), personal documents and other data you have saved on your computer over the years.

In order to back up data from your computer, you will need two things, hardware and software.

The hard side…

So, with that in mind, what options are available to back up and restore your data in the event of a computer emergency?  Well, a typical backup solution consists of both hardware and software, so let’s take a look at the different types of hardware with the following chart before we go into further detail.

USB flash drives are the newest medium available, ranging in size from under one gigabyte to at least 256GB, although you can expect to pay a hefty premium for larger sizes.  The main advantage of USB flash drives is their size:  They easily fit in a pocket or a keychain, and can be kept just about anywhere.  Of course, the disadvantage of this is that they occasionally end up going through the laundry.  One concern about the medium is how reliable they will be over time.  Some manufacturers offer lifetime or ten-year guarantees on their flash drives, but these only apply to the drive itself, and not to any data you may have stored on it.  Also, like discs and tapes, you can periodically buy several flash drives inexpensively and copy your data to them, reducing the likelihood of total data loss in the event of one failing.  If you do not have a lot of files to back up, USB flash drives are the obvious choice.

External hard disk drive systems have been around for many years, originally as proprietary systems which required specialized interfaces and cabling, evolving to the common external hard disk drives available today.  Current systems place a 2.5” (notebook) or 3.5” in an enclosure, with USB, FireWire and/or eSATA connectors for attachment to a computer.  External hard disk drives systems based on the 2.5” hard disk drives used in notebooks are physically smaller than those using 3.5” hard disk drives installed in desktop computers.  They often store less information and are not as fast as their larger counterparts, but make up for it in portability—some as small as a deck of playing cards—and often require just a single cable to provide both power and a data to their host computer.  External hard disk drive systems based on 3.5” hard disk drives are often less expensive and faster than their smaller brethren, but larger (about the size of a hardback book) and always require an external power supply adapter, since desktop 3.5” hard disk drives require additional electricity.

When purchasing an external hard disk drive, I would recommend looking at the warranty, keeping in mind that warranties only cover failure of the device itself and not the recovery of any data stored on them.  Also, check what type of connections it has for both data and, if applicable, power.  USB connections are recommended because they are the most common; however, purchasing an external hard disk drive enclosure with several types of connections will give you some flexibility, in the event that the computer to which you are restoring your data does not have a USB connection available.  If an external hard disk drive enclosure requires an external power source, I recommend buying one that uses a standard “barrel” connector for its power jack, as opposed to the proprietary multi-pin connectors used with some external hard disk drives.  In the event that you lose—or are forced to leave behind—your external power supply, a standard power source will be easier to replace.

There are a variety of sizes and formats of optical discs, but the most common are CD’s, which hold 650MB and DVD’s, which hold up to 4.7GB per side.  Both recordable CD and DVD formats include discs which can be written to once (CD-R and DVD±R) and/or multiple times (CD-RW, DVD±RW and DVD-RAM).  I would recommend avoiding the reusable “RW” discs, since they can be written a finite number of times, after which they lose the ability to retain (re)written data.  The DVD-RAM format handles rewriting better, but uses special optical discs that may be more difficult to find and expensive.  The 650MB stored on a recordable CD may seem very small these days, but they are inexpensive and a single CD might hold several years’ worth of correspondence and documents like tax records.  Recordable DVDs hold about seven times as much data as a CD.  While individual CDs and DVDs may be too small to backup your computer’s hard disk drive, backup programs allow you to back it up across a set of discs; we’ll talk more about backup software later.  You will still need to swap discs in and out of your CD/DVD drive as you record your backup to them.  Recordable Blu-ray discs are also currently available in capacities up to 50GB, however, both Blu-Ray disc recording drives and the media they use are expensive and may be difficult to find.  One concern about early recordable optical discs is that they may degrade over time, due to either latent manufacturing defects and/or the composition of their materials.  Check with your disc vendor to make sure the discs you purchase for use are archival quality.

Tape is the oldest backup medium, with usage dating back about half a century.   As such, it has arguably withstood the test of time, although proper storage of both media and the equipment to read them becomes an issue.  Today’s tape backup systems store from tens to hundreds of gigabytes of data—and even more with compression—and are highly reliable, which is one reason they are still used.  A tape backup system is expensive, though, with tape drives running from the hundreds to thousands of dollars, and individual backup tapes in the tens to hundreds of dollars range.  Tape is no longer widely used as a backup medium on the desktop, but it is still used in the enterprise, where the costs of maintaining tape drives and storing backup tapes is less of a concern.  Tape might fill a niche for some, though.

…and the Soft Side

Just as there are several different types of devices to back your data up to, there are several different types of programs with which to back your data up to those devices.  Although there has been a lot of consolidation over the past few years and the lines between types of program have blurred, they can still be classified by what features they originally started with, since that is where they will be strongest, performance- and feature-wise.

Let’s take a look at the most common types now:


Archives are not just for scholars

Classic archive programs are normally used to compress a large infrequently-used file into a smaller one, or to store a collection of several files in one compressed “container.”  This is usually done in order to transfer files over slow network connections, or to use less media when copying files to a disk for transport. The archived file(s) can then be expanded on arrival. However, these same benefits of reducing the size of files for transport make archive programs useful for backing up files.  Archive programs compress files to the smallest size possible according to the compression algorithm used, so that the resulting archive(s) use up the least amount of space.

Archive programs tend to use standardized formats such as .7z, .RAR and .ZIP, can often open archives created by each other and, increasingly, create archives in each other’s native formats.  Most other types of backup programs do offer some sort of file compression feature to reduce the amount of space required for a backup, but they typically do not do as good a job as dedicated archiving programs, resulting in backups which use up more space.  Many archive programs allow you to password-protect their archive files, so they cannot be viewed or opened without first entering the password.  One concern about using an archive program for backing up your files is that while they may technically be capable of doing so, they are not typically designed for this use.  In the event of an error with your backup archive, the program’s technical support may be of limited assistance in repairing very large archive files.

Like their archive program counterparts, “classic” backup programs are designed to store many files inside of one file using some form of compression, although some may not use compression in order to speed up the backup process.  Unlike an archive program, though, most backup programs use a proprietary format which only they can read, and often write to specialized media, such as tape or DVD-RAM discs, which are used almost exclusively for backups.  Backup programs typically have strong scheduling capabilities, allowing you to perform backups when a computer is not used, and can often backup files which cannot be accessed for backup when in use.  Another area where backup programs excel is in their handling of large backups.  Most backup programs allow you to “span” a hard disk drive backup across several DVDs, tapes or other media, and then restore files by reloading them in sequence.  Some backup programs allow you to back up only files which are new or have changed since your last backup.  These types of backups are called differential backups.  Many backup programs allow you to password-protect your backed up files, so they cannot be restored without your permission.  “Classic” backup programs are something of a rarity these days: however, they work well when used with a medium like tape for a backup mechanism.

Syncing up

File copying and synchronization programs allow you to transfer files from one location to another. This typically will not allow you to create a bootable copy of any modern operating system, but it is great for backing up data files from your computer’s hard disk drive to an external hard disk drive.  Backing up to a second internal hard disk drive, or even a different location on the internal hard disk drive is possible, but not recommended because loss or failure of the computer means loss of the backup.  A variation on copying is differential copying, which copies just new and changed files over to the external hard disk drive.  This is often called synchronization, or “syncing” for short.

Because an external hard disk drive is mounted and read as a regular hard disk drive by a computer, your back up files can readily be accessed on a different computer, even if it is running a different operating system.  While file copying and synchronization programs typically do not offer password protection, since they are essentially copying files from one hard disk drive to another, it may be possible to configure the external hard disk drive so that a password must be entered to access it.

Images: much more than just a pretty picture

All the previous types of backup programs we have talked about work with files, either individually or in combination.  While many disk imaging programs have similar capabilities, they distinguish themselves in that they can copy an entire file system, duplicating it so that that files are in the same location as on the original hard disk drive.  As disk imaging programs have the ability to duplicate a hard disk in its entirety, they can even copy the space occupied by deleted files, allowing you to use the cloned (copied) disk to recover files deleted from the original hard disk drive, which is why similar tools are much used in computer forensics.

A typical use for disk imaging programs is when upgrading a computer’s hard disk drive, as cloning the old hard disk drive’s data onto the new one generally results in new hard disk drive with the operating system, applications and data from the previous hard disk drive, usually intact and ready to boot up.  In an enterprise, computers may be secured to prevent this data leakage software, although in a home environment, a more likely reason is that a computer is configured to run several different operating systems. This typically does not interfere with the imaging software from making a back up copy of the hard disk drive, though, just booting after an otherwise-successful restoration of data.

In additional to copying from hard disk drive to hard disk drive, some disk imaging programs may allow you to span backups across multiple CDs or DVDs, or backup your hard disk drive to a server.  Another benefit of disk imaging programs is that they allow a “bare metal” restore:  In the event a computer’s hard disk drive fails, a restore disc can be booted from and the disk image loaded onto a new hard disk drive.  When finished, the computer is rebooted and will start exactly as it did after the disk image was created.  This could still work even if the entire computer was replaced, although the operating system might not boot up successfully unless (for example) the new computer’s hardware was identical to that of the old computer, or where a system is hardened to prevent data leakage. Such hardening might be implemented through hardware or software, or a combination of both.  If you are restoring to different hardware, or to a computer running a different operating system, it may be safer to restore just the data files from your back up, and use the new computer’s operating system and applications with your old data.  Some older applications, as well as proprietary applications from vendors, may require additional steps for reinstallation due to copy protection mechanisms.

Some hard disk drive manufacturers and PC manufacturers provide a disk imaging program with their disk drive either on a CD or available for download from their web site.

Blended backups

As noted at the beginning of the section on software, the lines between different types of backup programs have begun to blur in recent years, with many beginning to offer features previously available in other programs.  The types of backup mentioned above are not mutually-exclusive, and some backup programs may offer to perform several or all of the types of backups mentioned, above.  For example, the Windows Backup program that comes with Microsoft Windows 7 allows you to perform file backups and create system images.

Cloudy with a chance of data

Another class of backup which is becoming popular is storing your backup files “in the cloud.”  What this means is that your data files are stored on a server connected to the Internet, and you can access or even restore it from another computer connected to the Internet.  An advantage of this approach is that it makes your backups accessible wherever you have an Internet connection.  This is also, of course, the disadvantage.  Spotty, slow or absent Internet connectivity means limited or no access to your backed-up data.  There may also be concerns about the privacy of your backup and long-term viability and availability of the service that hosts it.

An enterprise whose business depends on the continuity of their operations may use the “cloud” for off-site backups.  In this case, though, the business may own the remote facility or obtain it under service from a specialist provider.  That does not mean that off-site backups for home computers are a bad idea, and we will discuss this further on.

Because the focus of this article is on physical backups that you can take with you in an emergency, we shall skip further discussion of cloud-based backup.

You’ve got mail! (And photos and letters and tax returns)

We have discussed, in length, both the software and the hardware used to backup a computer’s data, but one thing we have not gotten into is what exactly is it that you back up?

If you were to ask what the most valuable part of a computer was to most people, they might respond with an expensive part like the CPU or the video card, or, if they use a computer for business, any special software they might have purchased for business use.  However, it is usually possible to replace a computer’s hardware and software, although it may be difficult to do so for an older computer or for software that is no longer published.  People use computers for a variety of tasks, but typically those tasks come down to creating or manipulating data in some sort of fashion, and that is what is precious or unique about your computer; the data which you created on it.  Of course, if you are using a proprietary program to work with your data, it is a good idea to make a copy of that as well, just in case something happens to the program installed on your computer.

Data, data everywhere

So, with this in mind, what exactly should you be backing up?  Well, on computers running Microsoft Windows, most programs store your data in a folder named “C:\Documents and Settings\{username}” (on computers running Microsoft Windows XP and earlier) or “C:\Users\{username}” (on  computers running Microsoft Windows Vista and newer), where “{username} ” is the name of the account you use to log on to Windows.  However, some older programs store their data in a custom folder located in the root of the C: drive, like “C:\OLDPROG”.  Also, sometimes people get ‘creative’ about where they store their files on a computer.  Most backup programs will prompt you to choose which folders to back up the first time they are run, and this can be adjusted later, as needed.

If you are in doubt about where an important program stores its data files, contact the company’s technical support for assistance.  Tech support engineers are usually much happier when helping customers locate and back up data before a disaster occurs.  Unsurprisingly, so are customers.

If you choose to perform a “whole disk” backup using a disk imaging program, you will have all the files on your computer, but this can take more time to run and require more space.  In addition to restoring the entire disk, most disk imaging programs allow you to restore folders or even individual files.

If you are not sure about which files to back up, then a full backup may be the best solution.  While such backups may take more time to run, it will be a lot easier for you if you backup files that you never will need to restore, as opposed to needing to restore files that were never backed up!  Some computer manufacturers offer an integrated rescue and recovery or one-button recovery solution which automatically manages everything for you.  If you are buying a new computer—perhaps because your old system was destroyed or lost—you might want to look for this feature.

Time keeps on slipping

Another frequently-asked question about backups is this:  How often they should be run?  Some backup programs come with an automatic scheduler to run them on a fixed schedule, like once a day or once a week.  Others operate manually, allowing you to determine the schedule.  The answer, though, depends on a number of factors, such as:
•    How much data can you afford to lose?  Is a single day’s lost acceptable?  What about a week?  A month?
•    How much does it cost to make a backup, in terms of consumables like DVD±R discs?
•    How long does it take to perform a backup?  Minutes?  Hours?

Once you factor those three expenses, you can generally come up with a backup interval.  I find that for most people, somewhere between a day and a week is the norm.  People may also choose to back up some files more frequently than others, particularly if the data is very valuable or it changes frequently.

There can be only one… but many is better

An important thing to keep in mind is that you do not have to use just one type of backup method, or have only a single backup:  You might choose to clone your hard disk drive using disk imaging software once a month, while making synchronizing new and changed files on a daily basis.  You might also have several sets of media for performing backups:  For example, you could use two external hard disk drives for backups, and perform a back up each week to one of the hard disk drives.  This way, you would have two levels of backup, in case a problem occurred, or you needed to go back and restore data from the previous back.  A full backup of a computer, coupled with incremental backups of new and changed files, would provide similar functionality, allowing you to restore different versions of a file over time.

Sometimes your data needs a vacation

In addition, another thing to consider is where you store your backups.  Keeping them at home in a desk drawer is fine, but what would happen if you could not get home for some reason, or into the room in which they are kept?  This is one area in which a cloud-based backup solution might be ideal, however, another solution would be to keep a copy of your backup files—a backup of your backup, if you will—with a trusted friend or family member.  You could even store your backups at a bank or with your lawyer. If you do choose to do store your backup offsite, be sure to protect it with a password, though.

If you are in an area that is periodically subject to disasters such as floods, earthquakes or fires, it might make sense to choose a friend or relative who lives outside the affected region.  If nothing else, this provides a great reason to visit them!

Immortality for your data

Lastly, a final consideration is the life of your backup media:  Tape drives, tapes and hard disk drives are mechanical in nature and just like any other mechanical component will eventually fail.  Optical media can be scratched or degrade over time.  Even USB flash drives can only be written a finite number of times.  With that in mind, you should think about how long you wish to back up to a particular piece of media before you replace it.  Most modern tape backup systems keep track of how many times a particular tape has been used, and will notify you when it needs to be replaced.  For hard disk drives and USB flash drives, my rule of thumb is use it for half the length of the manufacturer’s warranty; so, for a hard disk drive with a five year warranty, I would use it for about two-and-a-half years before looking to replace it.  For optical discs containing your backed up data, I would suggest verifying they are readable on a yearly basis.  Do not wait, though, until you are having problems with restoring your backups.  Regularly replace your backup media, and periodically test that your backup was successful, preferably by restoring a small amount of data onto a different computer.  This helps ensure that your backup program was successful, and gives you a chance to test restore procedures before there is any trouble.

To download this Whitepaper on on hardware and software data backup options, click here.

Editors Note: The author of this post, Aryeh Goretsky serves as Distinguished Researcher at global security software developer ESET and frequently contributes to the ESET Threat Blog.  A Microsoft MVP since 2004, he is active on a number of professional and technical mailing lists and forums. He lives in Southern California with his dog and several years’ worth of backed up data.

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