You can answer it if you just presume the backup is to basic or advanced disk or tape, and duplicated to the same type of media.
basic disk > basic disk
advanced disk > advanced disk
tape > tape
... or you assume that the back and duplication are made to media with the same performance.
In which case, a backup will be quicker.
Why ...
A backup is one 'process'
A duplication, is a restore from the backup media, followed by a backup to the other media, therefore, this cannot be quicker than a backup.
BUT ... I've been thinking about this, and depending on what you are backing up I think would change the answer.
It is reasonable to suggest the above is true if everything is running perfectly, and you are backing up say one very large file.
If you then run a backup on many small files, it is known that this would be slow, as each file has to be opened/ closed etc ... a killer for performance with any backup software (which is where flash backups come in).
So, in this example, the duplication could well be quicker, as it doesn't have to open/ close all the files
Consider also, a backup that is skow as the clilent connection to the media is a slow network connection - here, the duplication would be quicker again as the network isn't involved in the duplication.
Soooo .. answer is ' it could go either way depending on what you are backing up and the environment.
Martin
