Difference between backup and archiving

Archiving is a process of moving inactive or infrequently accessed data from primary storage to other tiers of storage. Usually, it is moving from expensive to cheaper storage. For example, from expensive SAN lun to a NAS device or optical media. The primary information is moved to other media in this case. Backup will create a second copy of the information in another media such as tapes. So archiving the data does not eliminate the need to backup the data.

You can setup rule to archive you data. It maybe based on last access time, file type, etc. Once the file are written to secondary storage, a stub (file tag) is left on the primary storage to point to the secondary storage. Thus, space is freed up from the primary storage. When user accesses the file, the archiving software will retrieve the file from secondary storage. The stub has all the info about the location of file on the secondary storage.

Therefore, administrator should have a backup strategy on backup because archving does not keep a second copy of the file. Depending on the secondary storage, they can backup the secondary medias or running incremental backup on the primary storage. Check and make sure the backup software is compatible with the archiving software. Some of the backup software are not extended attributes aware and will cause a lot of issues.