How to clear up backup space on external drive

Among other backup sets, I have a Norton 360 backup running every night to back up my documents directory. It backs up from one 1 TB external drive to another 160 GB external drive.  But while there are only 70 GB in "my documents", the 160 GB drive is now almost full with the backup set.

 

I *do not* want to manually delete "older" files from within "manage backup sets", which seems to be the stock answer to this issue.

 

I have seen suggestions to "delete older backup sets".  What does this mean?  My understanding of a "backup set" is an individual backup procedure – at least, that's how it appears within the 360 utility menus.

 

With Seagate's backup, I could delete older history directories based on the name (number) of the directory, but I don't know what I can safely delete from the backup disk with Norton. Under N360_BACKUP\ there is only one long-numbered subdirectory. Under that, there are subdirectories named }0, }1 and so on.  today, most of these show a modification date of October 27.  One shows October 26, and one shows October 28.  The backup.@db file shows October 28.

 

It seems one solution is to delete the entire N360_BACKUP from the backup drive, and let it start fresh tonight, though that leaves me temporarily unprotected. 

 

On a related note, I do an occasional manual Norton 360 backup set of my 1 TB drive to another 1 TB drive to keep offsite.  Under N360_BACKUP\ on this drive, there are two long-numbered subdirectories.  In this case it looks like I can delete the older subdirectory.

 

Thanks.