[Brass]

I've got a client for whom I've implemented a fully automated Retrospect backupsystem writing to an external FireWire hard disk. It works quite well and offers a lot of flexibility.

However, Retrospect is not so good when dealing with single drive Tapes, CDs and DVDs. It can be done, but requires significant user interaction (unless I'm missing something).

The client has one file that needs to be backed up to offsite storage daily. Removing the external hard drive at the end of the day is not an option, as the fully automated backups occur during the night (for several reasons).

Currently, the client is burning this one important file to CD-R every day, just using the Finder.

This seems to me to be a real waste of space and CDs.

They could use CD-RW, but OS X seems to treat them as CD-R anyway, and that just makes them twice the cost for no advantage. Is there any trick to getting CD-RW to work reliably in OS X? Seems to work fine in OS 9.

Even better would be using CD-R with multi-session burning. Is there some way of enabling this in the Finder? Or otherwise some other easy way to use multi-session burning that even this relatively computer illiterate user could cope with?

[Art Vandelay]

I have no problems with CD-RW in OS X. Use Disk Copy or Disk Utility to erase it. Also, Disk Copy does support multi-session CDs. It's an option when you burn the CD.

[Brass]

Originally posted by Art Vandelay:
I have no problems with CD-RW in OS X. Use Disk Copy or Disk Utility to erase it. Also, Disk Copy does support multi-session CDs. It's an option when you burn the CD.

But how do I make it easy for a user to use Disk Copy to backup this one file in a Multi-session backup? What are the steps involved. It's an awful lot more complex that just dragging the file to the disc then right-click and "burn".

[Brass]

Any way of doing multi-sessions using hdiutil? Maybe I can write a script that uses that (or even a Cocoa App).

It would be nice if the user just dragged a bunch of files onto a script/application, and it came up with a dialog saying "Burn new session to CD?" and gave you a field to enter a name for the new session/partition and an OK button. Dead simple for novice users!

[Art Vandelay]

Probably the simplest thing for you to do then is to just erase the CD-RW in Disk Utility or Disk Copy. The OS will then display the standard dialog for when a blank CD is inserted. Pick open in Finder and it will be just like what they are doing now, except they are reusing the same CD.

[Brass]

Originally posted by Art Vandelay:
Probably the simplest thing for you to do then is to just erase the CD-RW in Disk Utility or Disk Copy. The OS will then display the standard dialog for when a blank CD is inserted. Pick open in Finder and it will be just like what they are doing now, except they are reusing the same CD.

No, we don't want to delete the existing data. We want to preserve old backups, not replace them.

[Brass]

Aha! Looks like I can do it with the hdiutil command. I just need to write a little Cocoa wrapper for it to make it nice for the users. If anyone's interested, the relevant hdiutil command lines are:

Code:
hdiutil create tm-image -size 5m -type SPARSE -fs HFS+ -volname NewVolume

hdiutil mount tmp-image.sparseimage

hdiutil eject <dev-name>

hdiutil burn tmp-image.spaseimage

Then between the "mount" and the "eject", just copy the files to the mounted volume. (The dev-name can be gleaned from a df command output, checking with the volume name).

Works nicely. Now for the Cocoa wrapper.

[darrick]

i'm interested. i back up to a second hard disk every week but i need to do off site cds, too.

[Brass]

I'll post here when the application is ready to roll. Almost finished the GUI.