Testing archive integrity

A critical part of making backups is testing the integrity of the backup on the final storage medium. KDar uses cyclic redundancy checks, or CRCs, to check the integrity of an archive.

With an archive already loaded into KDar, select Archive->Test from the main menu to begin the integrity check. This test is best performed by opening the archive directly from the storage medium on which it resides. It may take a while, but it is worth knowing that your data is intact.

NOTE: the archive integrity test does not guarantee that you will be able to restore your data onto a new disk. For example, if you try to restore a file which has extended attributes onto a filesystem which does not support extended attributes, you will not be able to restore the extended attributes. Another example would be if you “upgraded” your CD-ROM drive, and it could not read the old CD-R's that you made two years ago. Another possibility is that KDar might have a bug which prevents you from restoring a certain type of file, for example.

To maintain the highest probability of being able to recover from a catastrophic filesystem failure, perform a full restoration on another hard dive, partition, or storage device, to verify that you can perform complete restoration.

Read the document “GOOD_BACKUP_PRACTICE” in the dar source doc directory, for a good background on making reliable backups.