View Full Version : Full backup drive question

10-02-2009, 12:06 PM
I am considering Super Duper for my backup needs i have a quick question before downloading and trying it.

I'm very happy with Time Machine because it does a great job managing backups and deleting the oldest versions to make room for new backups as needed. However, TM (according to Apple) is only made to work with your system drive, so all those secondary drives either in your MacPro internal bays or connected via Firewire cannot be backed up with any reliability. My question to you is how does Super Duper handle a full backup drive? Is it similar to Time Machine? I have tried several other solutions and none of them handle this issue well at all.

Thanks for your time.


10-02-2009, 03:40 PM
SuperDuper! will fail (and typically log "no space left on device") if the drive fills.

10-02-2009, 03:58 PM
Can you make any recommendations?

10-02-2009, 04:12 PM
Well, I don't know. I'm not sure what, exactly, you expect software to do when the backup disk is full...

10-02-2009, 06:30 PM

To amplify Dave's answer a little, SD, unlike Time Machine and some other methods of backing up, does not do ANY incremental backing up. That is, every time it creates a new backup, whether clone of all files or copies of some subset(s,) it puts the new material on the target volume but does NOT retain any older versions. Hence, in a "volume full" situation, it has no way of "managing backups and deleting the oldest versions to make room for new backups," as you put it.

In other words, it has no multiple versions to manage, nor plural backups to choose from. It has only the immediately preceding backup, which it overwrites as needed. Hope this helps.

There are some rather complex (and expensive) commercial backup solutions available which will do various types of true incremental backups, if that's what you want, but even with them, I am not certain of how they handle the "volume full" situation. Retrospect is the one I was familiar with, but now have not used it for about four years since leaving the company where it was employed. At that time, in a target full situation, it would simply copy until that point, then stop, with a message of what it had and had not done, and wait for input/instruction. As Dave said, I am not quite sure what else it could do.