Backing up a backup ?

I hope that I have interpreted your requirement correctly:

I can't see that you could back up directly from one USB device to another without the interposing 'intelligence' of a rudimentary operating system.

Nor would it be a good idea. You have no idea of the integrity of the first backup, so surely it is better to duplicate the backup of the original data rather than risking the duplication of a flawed primary backup.

Fraser

I agree with the previous poster that you should just make your second offsite backup directly from the ReadyNAS. I believe the ReadyNAS's have a pretty simple method for backing up, so just use that.

One common way that people do offsite backups is to label your two USB hard drives as A and B. Once a month, backup one (A) and bring it offsite, and when you come home bring the offsite one (B) home with you and run a backup to leave home for the month. Repeat monthly.

If you use A for odd months and B for evens, it will be easy to remember if you skipped a month or what month each was last backed up. I keep a piece of paper taped to mine with the date of last backup scribbled on it.

Agree with previous posters, always backup from the original, source files.

If you are looking for some software to assist you I have used SyncBack for years, it allows many options for backups, including mirroring of the disks.   There are paid and freeware versions available.

We use the paid version in our small home based business to mirror data files onto a NAS drive every 30 minutes and also to external USB disks which we move offsite in a similar way to LeeToms suggestion.

Once you have the backup jobs setup you can just run them adhoc or to a schedule. The software also can verify the files which gives some comfort that your efforts have been worthwhile!

Richard

Folks - thanks for the responses. That does make a lot of sense and with the backup jobs already set on the NAS a very simple solution. Off to Amazon

Thanks again for the help

James