Backing up
Routine backups are strongly recommended for any document stored on a computer. Magnetic media are susceptible to a variety of problems, and a storage device such as a hard disk should never be the sole repository for your data. Extreme heat, cold, sunlight, and the presence of electric and magnetic fields can all contribute to the failure of magnetic storage media, so a careful backup strategy will include optical as well as magnetic media.
It is easier to back up a database than it is to re-create it. Whether you should back up your data every day, several times a week, or less frequently is usually determined by the amount of data you are adding to your databases and how difficult it would be to re-create your files in the event they become corrupted.
A strong backup strategy is one that employs multiple media and backs up on a consistent schedule. This affords you some protection against the failure of a single hard disk, removable disk, tape, or other media.
In its simplest form, backing up means copying your files to another disk for safekeeping. As your files become larger or more numerous, you might need to use a third-party program to do a proper backup.
A good third-party backup program should provide multiple copies of a database as sources for restoration. A scheme involving rotating backups can accomplish this. Typically, this method involves separate backup copies over no less than a two-week rotation. The file is backed up to a set on day one, a new set on day two, until ten sets of backups exist (assuming a five day work week). On the eleventh day, the first set is reused. This type of rotation ensures that a lurking problem will not spoil your chances of a complete file restoration.
For very important files, it’s a good idea to store backups at an off-site location. Fires, earthquakes, and other disasters can and do occur, and there is added safety in securing copies of your vital files off-site.
Note  To avoid possibly damaging the only backup of your database, make sure that you copy the database file you want to restore and leave the original backup file unchanged in the backup folder. Do not move the database file out of the backup folder, and do not use FileMaker Pro to open the database file that is stored in the backup folder.
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Example backup script