Need to erase backup disk?
 

Hello.
I have a powerbook running 10.2.8 with a 40Gb (nearly full) drive, and a 120Gb (60 Gb free) firewire drive. I need to backup the 40 Gb drive, so I did some research, bought superduper, ran it, then realized to my embarrassment that I had a deep misunderstanding about how backups work. Can someone help?

I was planning to do a full bootable backup (files, applications, etc...) of the 40 Gb drive onto the space on the firewire drive. But a full backup would, as far as I can tell, erase everything that's currently on the firewire drive. I cannot do this, as I have many files on the firewire drive that I need that are not on the 40 Gb drive.

Is there some way to do a full backup of the 40 Gb without erasing what's on the firewire drive (short of buying another firewire drive)? Will copying to disk image do the trick?

Thanks to anyone who can help.

There are two basic approaches you can take that don't involve additional hardware.

- You can partition the drive into a "data" volume and a "backup" volume. A program like iPartition can be used to do this "live" with data in place, or you can use Disk Utility if you can (temporarily) move the files off the drive.

- You can use a sparse image, as discussed in the FAQ.

Either will work, but the former is preferred because it's faster and will allow you to boot from the backup if (when) disaster strikes.

Partition size question
 

When partitioning a volume to do a complete, bootable backup should the partition exactly match the size of the disk drive to be backedup or something else. The reason for the question is that I don't want to waste space by partitioning larger than necessary. In my case I have a 80GB PowerBook, but system profiler says I have a drive capacity of 74.53 GB capacity and further that I have a volume capacity of 74.41 GB. So on my external hard drive to I write an 80 GB, a 74.53 GB or 74.41 GB partition? Or is there another size that I should write to compensate for the inner workings of SuperDuper? Please advise to my email as well as here.

Leave yourself a bit of headroom, Bob, and create a 76GB partition or so. The 74.41 is because drives are advertised as "Billion Bytes", as opposed to actual "GigaBytes", which are in multiples of 1024, not 1000.

Marketing.

Anyway, your partition need only be as large as your largest anticipated data storage, plus about 20%...