Need to restore different versions of files (for example, file systems used for word processing) 

• Do daily incremental backups every working day.

• Do not reuse the same tape for daily incremental backups.

This schedule saves all files modified that day, as well as those files still on disk that were modified since the last backup of a lower level. However, with this schedule you should use a different tape each day because a file changed on Tuesday, and again on Thursday, goes onto Friday's lower-level backup looking like it did Thursday night--not Tuesday night. If a user needs the Tuesday version, you cannot restore it unless you have a Tuesday backup tape (or a Wednesday backup tape). Similarly, a file that is present on Tuesday and Wednesday, but removed on Thursday, does not appear on the Friday lower-level backup. 

Need to quickly restore a complete file system 

Do lower-level backups more frequently. 

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Are backing up a number of file systems on the same server 

Consider offsetting the schedule for different file systems. 

This way you're not doing all level 0 backups on the same day. 

Need to minimize tapes 

Increase the level of incremental backups done across the week.  

This means only changes from day to day are saved on each daily tape.  

Increase the level of backups done at the end of the week.  

This means only changes from week to week (rather than the entire month) are saved on the weekly tapes.  

Put each day's and week's incremental backups onto the same tape. 

This is done by using the no rewind option in the ufsdump command.