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SBlumenthal
09-16-2006, 06:21 PM
1. I have a 250 GB iMac that I want to Backup with SuperDuper. I am shopping for an external HD. Is it OK to backup a 250 GB Source Drive with a 250 GB external HD, or should I get something larger?

2. I just read this in your manual...

...it is possible that a user won’t notice a problem in a “bad file” until
they’ve already overwritten their backup, thus losing any chance of recovery with a “full copy”. While this is a problem for some, we have a good solution: rotate more than one full backup. Any need for this kind of “temporal rollback” can be significantly reduced with a single rotation – say, on a weekly basis – and nearly eliminated with two, a weekly and a monthly. It’s incredibly rare that, on a non-archival basis, you’d need to go back more than four weeks.

I'm a little confused. From what I gather you have a primary ext. HD that is constantly hooked up to your source machine and backs up daily. Then a second ext. HD that you hook up weekly or monthly for a periodic backup. But, if you have that "bad file" how would you know until something does go wrong, and by then you could have backed it up to both of your backups.

Have I completely missed the boat on this? if so, please explain...

Thanks,
Steven

dnanian
09-16-2006, 11:34 PM
Yes, you can still have the problem. As I said, the likelihood is reduced with a rotation, but the risk is there (as it is with any backup, really).

SBlumenthal
09-17-2006, 02:31 AM
OK, but was the actual process of utilizing the rotation, as I understood it, correct?

dnanian
09-17-2006, 10:24 AM
Yes: it's a matter of "holding" older copies of files until a certain amount of time passes. That copy is then rotated and replaced with a newer copy.