Many backup strategies exist, from simple file copying to network based backus ona SAN or robotic tape library. This FAQ addresses some strategies for backup considerations.
Primary reasons for data loss are human error and hardware error. Human error is when a document gets deleted, modified, or lost. I personally experienced a thumb drive smashed in a car door! Hardware error is usually a hard disk failure.
Considerations in choosing software and hardware are often decided together based on cost, user capabilities, the amount of data to backup, and a balance between backing up for human or hardware error. Even lower priced home computers now have the ability to use RAID (Redundant Array of Independent Disks). The simplest RAID requires two hard drives with data getting saved to each of the drives simultaneously. RAID is totally transparent to the user and if one drive fails the other continues to merrily do its job. The computer will normally sound an audible alert if one of the drives needs attention. RAID is a great way of not having to reinstall the operating system, application software, and worrying about recovering data from backups. It addresses hardware failure well, but does nothing for the human error.
Recovering files due to human error (or hardware error if RAID is not in place) requires software to perform the backup and media to safely store the backup. Software examples include using Windows Explorer to copy files, writing a batch file, using Windows' backup software, file synchronization software, or imaging software such as Symantec Ghost or open source Clonezilla. The Useful Links and Further Reading section includes links to products or detailed instructions mentioned in this FAQ.
I would be negligent if mention was not made to a feature beginning with Windows XP called System Restore. If a new program, update to an existing program, or other modifications are made to the system that render it unstable or made undesirable changes, do not hesitate to try the System Restore first instead of resorting to more drastic measures such as restoring from below strategies. System Restore will not erase data files such as Word Documents, but will return the system to a previous point in time that you choose. See the link below for a nice article detailing how it works and how to use it.
An ideal backup strategy is determined by the value of what might be lost without a backup. The following strategies take into account the value of the system getting backed up.
A casual home user might have nothing to lose but a few jokes saved from e-mail, some high gaming scores, and a few word processing documents. In this case I doubt a backup is necessary at all.
At the next level the user might use a financial program such as Quicken and word processing documents that contain information that would be difficult to find or type again. There might be a large collection of photographs that can never be replaced if lost. This user's backup needs could be met by utilizing the Application software's backup features and by using Windows Explorer to copy the documents to USB devices, recordable CD or DVD, or external hard drives.
Adventuresome users can write batch file or Powershell scripts to automate directories that need backed up.
Windows 7 includes a backup program that can perform full backups and make a restoration, even in the event of a full crash, fairly painless. There is a link in the Further Reading and Useful Links for a Microsoft instructional page that includes a video. Another nice feature is that the backup file is a VHD (Virtual Hard Disk) file that can be "mounted" in another system. This makes the backup file appear as a drive letter, giving access to files on the other system while repairing whatever went wrong with the original.
Cloning involves making an exact image of the system's drive to another location, typically an external hard drive as other media would not have enough capacity. When restoring a drive from a cloned image one does not need to install the operating system, patch it up to date, reinstall applications and patch them, and restore data. It images the drive to the point in time the clone was made. Therefore, I recommend a combination of cloning after major changes are made to the system and using a less time consuming option to backup new files or minor changes between clones.
Clonezilla is free and will clone partitions or entire drives.It recognizes RAID and will even network to multiple machines at once.
Virtualization is very slick and useful technology. In the simplest of explanations, you install software on a "host" computer that can run another instance of an operating system (a guest computer) in a window of the host computer.
There are utilities that backup a system to a file that is a format of a guest virtual computer. Microsoft's Mark Russinovich of Sysinternals fame wrote a free disk2vhd utility, Windows 7's backup program saves to a .VHD (Microsoft Virtual Hard Disk) file, and VMWare has a free converter program to convert a physical machine to a virtual one.
What does this mean for backups? If you choose to backup a system to a virtual guest file onto a network share or an external disk drive, the guest can be booted and running at the point of time when the backup was made. The physical system that is down is now up and running virtually in a window of another computer.
I have also converted physical machines to virtual ones to minimize impact of key systems that are aging, out of warranty, or need replaced, but have software that cannot run on new systems. Ever get a new computer and wish you could get rid of the old one but are afraid to? Convert it to a virtual computer!
Take into account your needs and ask yourself: How important is the data? How important is it to have a functional computer? How fast do you need to get back up and running? How valuable is the time it takes to make a recovery?
I'll share my routine based on answers to those questions. I have two external hard drives. Their capacity is enough to have a full backup using Microsoft Windows 7's native backup program. I rotate the drives, keeping one on site and the other at an off site location. In the event of a fire, theft, or other disaster at my office I have the other drive with the .VHD backup file that can be mounted or run as a virtual machine on another system. The drive that is onsite stays connected for nightly scheduled backups. I also have a third drive that has a cloned image. Some old habits are hard to break.
Beyond the above strategies would require more detail and discussion than intended for this quick little FAQ.