How to permanently archive Time Machine backup?

Solution 1:

I would recommend using hdiutil to image the disk.

First, run diskutil list in the Terminal to see the identifiers for each disk. You'll want to note the identifier for your Time Machine drive (format is /dev/disk#).

Then, in the Terminal, use:

/usr/bin/hdiutil create -srcdevice /your/disk/identifier -format UDZO name.dmg

Where /your/disk/identifier is the /dev/disk# corresponding to your Time Machine drive, and name.dmg is the name of the output DMG. The UDZO format is the default compressed disk image format. The disk image will be a replica of the entire USB drive.

Solution 2:

I suggest you break it up into two parts: copy the files, then compress them. Apple has the simplest solution to copy files and you can use the Finder to do so; then try the disk compression routine, if you want to go that route.

Faced with this situation a few years ago at home, and having similar problems, I realized I was just jumping through hoops. I bypassed the entire compression and archiving routine by starting a new Time Machine backup on a brand new drive. I then stored the old TM disk off-site (my office.)

I've since extrapolated this concept into primary and secondary TM disks for each computer I now use (my iMac @ home, and the iMac and laptop @ work.) I swap drives weekly, using my home as off-site storage for my work computers, and my office for off-site storage of my home computer. If there was a catastrophe destructive enough to lose both sets of disks, I'd have a lot more to worry about than a loss of data.

For ultra-crucial files, (encrypted PDF files containing my novels, poetry books and scanned financial and other documents; photos & videos, etc,) I use both Dropbox and Google Drive.