Compacting Sparse Image Files
Murphy has been using SuperDuper for backups for a while now. Its flexibility and ease of use have helped it build up quite a following. Usually, Murphy sends his SuperDuper backups to a sparse image file. The sparse image file is a container that grows as you add more content. But what if content is removed from the sparse image file? That’s a good question.
The answer is that the sparse image file needs a little help to shrink. For example, let’s say you backed up your drive on Wednesday to a sparse image file. Then you deleted some big video files on Thursday and did another backup with SuperDuper on Friday. Your video files aren’t in the sparse image file anymore, but the backup is still taking up space on disk as if they were. The solution is simple. Use a simple command in the Terminal to reclaim the wasted space in your sparse image file. Just type everything in the line below, replacing the path and file name with the path and file name of your sparse image.
hdiutil compact path/sparseimagefilename
Here’s a tip in case you’re not used to working with Terminal. Just type hdiutil compact in the Terminal, followed by a space. Then drag the sparse image file from Finder into the Terminal window. The path and file name will be added to the command line. Hit the Return key on the keyboard and you’re done.
Murphy picked up an iomega drive
Some people might prefer SuperDuper. SuperDuper gives users a great deal of control and a multitude of options. Murphy posted a screencast about it a while back. SuperDuper hasn’t been updated for Leopard yet - but it should be soon.
Here’s the big draw to Time Machine: Backups are done all the time, providing the ability to restore many different verions of a file. With SuperDuper there’s a good chance you keep a single backup that only provides you with access to a single version of a given file. You could use SuperDuper to keep multiple backups, but not as easily as Time Machine (thorough review) does.
Click here for important observations about Time Machine
You want to buy a drive that’s larger than the size of the drive you’re backing up. The larger the drive, the more versions of a file Time Machine will be able to maintain. You can decide for yourelf how much drive you need, with portability and price as additional tradeoffs.
Here’s another drive
With hard drive prices down and your photo-music-video libraries at stake you’ve go no excuse not to back up.
11. January 2008 at 3:37 pm :
I’m a big fan of SuperDuper! and personally think that Time Machine is pretty useless (you can’t boot from it, it takes up huge amounts of disk space, etc.) However, unfortunately, SuperDuper! is not yet compatible with Leopard.
Until SuperDuper! works on 10.5, and in addition as an alternative to all of these, I strongly recommend using an online backup service. I use Mozy - for $5/month I have unlimited backups and currently have 100+ GB (that’s no typo - I mean 100+ GIGABYTES) stored online on their servers and can access my files from anywhere if necessary. I’ve tested the restore function and it works beautifully.
Even when SD works I still use Mozy, too, as I believe backups should be handy, but also save you in case of complete disaster (earthquakes, fires, flooded offices, etc.).
Of course, that’s just my 2 cents worth… but I sleep a lot better knowing that I can be back up and running in no time at all if the worst happens.
11. January 2008 at 7:27 pm :
It would be nice if you could boot from a Time Machine backup. But being able to restore from Time Machine after booting from the install dvd strikes me as pretty close. Not the same, but close.
I haven’t tried Mozy, but that sounds like a reasonable fee. I pay a little more for Bluehost which gives me 600 gigs of storage. But it doesn’t really have a backup interface. I kind of “do it myself” - sending up important files overnight.
Readers can see more about Bluehost here:
http://murphymac.com/mac-isnt-your-only-choice/
Check out Murphy’s post on rsync too. It can help with online storage:
http://murphymac.com/sync-iweb-with-a-third-party-host/
As for Time Machine being useless: I don’t agree. For a certain user class I think it’s perfect. Commit a hundred bucks to a backup drive and it will handle the needs for many users, including recovering from accidental changes to a file. The ease of restoring is a plus. We have to remember that tons of Mac users aren’t geeks, they don’t want to think about these things. Time Machine is perfect for them.
24. February 2008 at 9:13 pm :
Thanks for the sparse image tip. This is exactly what I needed to know.
FYI, please note that SuperDuper! v2.5 is now Leopard compatible (I’m a satisfied customer, not affiliated with Shirt Pocket).