A. The most common backup strategy is to perform incremental backups Monday through Thursday and a normal backup Friday. Incremental backups are fast because they back up only those files that changed since the last backup, marking the files as backed up. In the event of a failure, you need to first restore the normal backup, then restore any subsequent incremental backups.
An alternative backup strategy is to perform differential backups Monday through Thursday and a normal backup Friday. Differential backups and incremental backups are similar, except that a differential backup doesn’t mark the files as backed up. Therefore, files backed up Monday are still backed up Tuesday, etc. In the event of a failure, you need to restore only the normal backup and the latest differential backup.
Be sure to maintain more than 1 week’s worth of tapes. The best strategy is to have a rotation of at least 10 tapes and to rotate the tapes every 2 weeks.
If you want an extra backup for one-time use, consider a copy backup. A copy backup is a full backup, but the files aren’t marked as backed up. This type of backup doesn’t interfere with the backup scheme you’re using.
