drive won't unmount

[Khutch2]

I have two internal and one brand new external hard drive (firewire). My start up drive (40 gig) is partitioned, one partition is the start up (named Applications) and the other is just for data storage (aptly named Data Storage). The other internal drive is 250 gig. My goal is to "unpartition" my start up drive to restore it as a single drive. The reason was that my partitioned start up drive is maxed out, while the other partition has ~10 gig available.

So, I made a sandbox on my new external firewire drive, backed up each partition of the start up as a disk image on the other internal drive. I booted up on the sandbox and went to disk utility to "unpartition" the internal drive. I got the courage to hit the partition button and got an error message saying the drive Applications will not unmount. Tried several times and always get the same message. Data Storage seems to cooperate. Any suggestions?

[dnanian]

Ack! A Sandbox is not a backup! Your Home folder is still on the original drive. Erasing it will lose all your data. DO NOT DO THIS.

If you must, make a full "Backup - all files" to the drive. Name it the same as the original. Start up from it. You can then safely erase the original, since you now have a full copy.

[Khutch2]

Thanks, nearly an epic blunder.

What would you recommend? I have one 500 gig firewire drive and two internal drives. The first (original) internal drive is 40 gig partitioned into a 15 gig partition (start up) and 25 gig partition. The second internal drive is 250 gigs. My goal was to increase the size of the start up drive by unpartitioning into a single drive and then back up what would now be 2 internal drives to the firewire.

Here is the current state. The 15 gig start up partition is backed up to the fire wire drive (by SD) and I have simply copied the 25 gig partition to the other internal drive.

The way I understand it now is I cannot back up both internal drives to a single firewire drive. Do I partition the firewire drive and back up the two internal drives?

Thanks.

[dnanian]

That's right: you partition the backup drive and back up each source volume to its corresponding destination.

[sjk]

you partition the backup drive and back up each source volume to its corresponding destination.
Or back up to disk images, but presumably Khutch2 doesn't want to do that since it was the old method:

… backed up each partition of the start up as a disk image on the other internal drive