Table of Contents
Choosing the Right Backup Plan
You need to make the backup you wish you had made before you wish you had made it. So, how do you determine what that backup would be before you need it?
The first step is to decide your priorities among your conflicting goals of being easy, thorough, and inexpensive. You must give up some convenience for security and give up some security for convenience, and spending more money will buy more security and convenience.
There are certain files that are identifiably mission critical. These files should be saved to your U.Va. Home Directory Service. ITC will back these files up for you automatically as part of this free service to all students, faculty and staff of the University. As of this writing, files stored on U.Va. Home Directory Service are backed up every hour for the past 24 hours and every night at midnight for the past two weeks. Backups older than that can be restored from tape with human intervention, but within this two-week-long time span, you can restore your own backups from the U.Va. Home Directory Service Service Account, Group, and Directory Maintenance web page. Just log in with your blue.unix.virginia.edu ID and password and follow the directions given on the web pages.
These timed backups potentially save you from many human errors. If you overwrite or delete a file by accident, just restore the appropriate backup.
You are similarly protected from hardware failures. If your hardware fails, your files are unaffected and will wait for you until your hardware is fixed or replaced. ITC uses RAID 4, a special system that redundantly writes data to multiple drives so that if one of our disk drives fails, no data is lost. Even if more than one disk failed, the worst case is that we would replace the drives and restore your files from tape made on the most recent night, likely without any intervention on your part.
U.Va. Home Directory Service guards the survival of your files, so long as you maintain access to the network. If access to a file is too important to risk losing temporary access to it when your network link is down, you should keep a relatively current second copy of that file on your hard drive.
If you have Windows 2000 or Windows XP, you can automatically keep a local copy of any online file, including those on U.Va. Home Directory Service. Look for Synchronization Manager in the Windows Help facility available on your Start menu for details. It is a little arcane to set up, so likely you should not trouble yourself with this unless you really do have files that you cannot afford to lose access to during those rare times when the network is not available.
Choose well the files you keep on the U.Va. Home Directory Service. You have limited space for your files there. If this is not enough space for you, see your options described lower on that same Web page.
Some files need to be on my local drive, like my POPed Email or my hot-synched Palm-OS files. I want them backed up. If you know the specific folders you want backed up, you can make your own selective backup using the backup software built into Windows or provided by the manufacturer of the external media you will use to make your backup. Most external hard drives, for example, come bundled with backup software.
Realize that you will be more likely to make your backups if you do not need to change disks because the medium lacks sufficient capacity to contain your entire backup on one disk. The tedium and time commitment of changing disks during an extended backup makes backups the kind of chore people do not stick to. Even if a backup is slow, if you can start it and walk away, then you can back up your hard drive during lunch or after work. Check out the capacity of various media commonly used for backups these days.
Realize that when you make your own backups, you want to have two sets of backup disks and alternate between them, so you'll still have the previous backup to turn to if something goes wrong during the backup process. You also want to store your backup disks in a safe place securely separate from your computer. You don't want one fire or other disaster to destroy both your computer and your backup disks.
I'm concerned that I may need backups of files saved in locations I may not be aware of. If you are sufficiently concerned about the security of all the files on your computer -- even the ones you can't dependably identify -- then you would be best served by following a regular schedule of backups involving both Full and Differential backups. This will give you the next higher level of security with the least increase in inconvenience.
For the sake of simplicity of wording, I'll assume you use some sort of disk as your medium. You should be using four disks or disk sets for your backup. You will use only one of these four each time you backup your hard drive. Two will be for Full (large) backups and the other two will be for Differential (small) backups. It is important to have two of each type because you want to avoid discovering that your hard drive has acquired bad sectors in the middle of an important file while you are in the middle of backing up that file onto the backup disk that had the only backed-up copy of that file.
To be clearer about this: When you start backing up your hard drive onto a removable disk, you begin by wiping out whatever backed up files you already had on that removable disk. It is better if that disk is not your most recent backup.
The first time you back up your hard drive, either use a medium with enough capacity to hold all your files on your hard drive, or set aside enough time and disks to swap disks until the backup is complete. Once you have a full backup, (Full#1), the next time you back up your hard drive, you can do a Differential backup (Diff#1). It will take less time and require less capacity from your backup medium because you are only backing up the files that are newer than those already backed up on Full#1.
From this point on, when you do your most frequent backups (daily or weekly, depending on your perceived level of risk) alternate between Diff#2 and Diff#1. Keep notes to know which was the most recent and use the older of the two for each new backup.
As time goes on, the differential backups will get larger and require more time and more space on your backup medium. Over time, more files will have changed or been added since your Full backup. When this becomes a problem, make your next Full backup. While the Full backup takes much more time and more space on your backup medium, subsequent Differential backups will be shorter than they have been. As you need to make new Full backups, alternate between Full#2 and Full#1.
If you ever need to restore a file, first look for it on your most recent Differential backup. If it is not there, look for it on your most recent Full backup. These two backups should have copies of every file your hard drive had on it at the time of your most recent backup.
I want insurance against corruption of my Operating System and my applications. None of the backup solutions discussed up to this point will dependably offer a way to restore your computer to its former level of functionality if the Operating System or applications become corrupted by human error, virus, hardware failure or any other means of corrupting the huge collection of interdependent software typical to a modern personal computer. These solutions save your data, but not the software itself. For that, you need an Image backup of your hard drive.
The problem is that a Full backup copies file-by-file from the hard drive, but it snags while trying to back some of the open files in use by the Operating System. The Operating System gets in the way of both backing up and restoring the complete system.
A special class of backup software gets around this by the use of special tricks that have changed over time. The thing to know is that an image backup can restore your system to exactly what it was while you backed it up, but a normal full backup cannot.
If you have a DCI computer, the System Restore Disks that you got with it were made with this kind of image backup software. Since they restore your system to the exact configuration it had when it was originally purchased, this is a quick fix for corruption of the OS and applications, though you then lose all files and applications that have been added to the system after it was purchased.
Still, having the System Restore Disks complements your other backups well because you can restore the system, then reinstall any added applications, then restore your data files. This is a big advantage over systems that do not have these System Restore Disks.
If you do not have a DCI machine, or if you want more current images made of your system for a more immediate recovery of your system should anything go wrong, you need to purchase software, like Symantec's Ghost and use it, likely in combination with other backup procedures described above. You should make a new image backup before installing new software, new hardware or before making significant configuration changes that could have consequences from which you may want a safe exit. Once the changes to your hardware or software prove to be reliable, you will want to make another image of the hard drive so that you can restore the system to the state after the change.
Norton Ghost versions 9 and 10 can make both image backups and incremental backups. Neither offers the option of a differential backup. You would have the option of using Ghost for your image baseline backup and then using some other backup software for the differential backup.