Time Machine Backup Time/ Space

/ 3 November 2007

My long-term setup for Time Machine includes making only manual backups, one per weekend. That fits well enough with my old setup (with SuperDuper!) and it means no in-the-background or space-consuming backups. I did my backup for this weekend this morning and got pleasantly surprised by a few things.

First off all, it only had 184.5 MB to transfer after one week of running without backing up or taking any software updates (SuperDuper! had 1 GB to transfer). It also only took 15-20 minutes (SuperDuper! took 30 minutes) to make the backup. Now, the main reason for this pleasant experience with my first weekly backup is the result of a few key improvements that Leopard has over Tiger. The Leopard engineers spent long hours rewriting the way many of their key application’s back-end user databases were stored to make them more Time Machine-friendly. Where whole iCal calendars were once a single file in Tiger, each event is now a single file in Leopard. Adress Book and Mail both have spread out their databases into more files as well. Third-party software like MarsEdit and NetNewsWire also have back-ends like this. Now these advances would also decrease the space amount of a SuperDuper! backup as well.

Overall I’m quite impressed and pleased with the experience I’ve been having with Time Machine after how anxious I was about how trusting it would be in the months before installing the OS. Plus, the disk I’m using isn’t set up directly, but a network volume. You’d expect that a network volume would be slower, right, but no, it’s just as fast as a local disk. Now that may change if both my MacBook and the host iMac are backing up at the exact same time, but overall it seems to be working out just fine.

Time Machine does have it’s surprises though. Since I’m using just manual backups I don’t expect the computer will initiate a backup on it’s own. But, I learned today that Time Machine is designed to compile two runs into one final backup step. I initiated the manual backup, it ran it, and then did a second one right after. This is to have a more accurate backup step, but it was kind of shocking. These two backup runs get compiled into one final restore step.

It does seem as if the setup we’re using for my MacBook will work in the long term. That setup is with my mac knowing the disk as a network volume to be able to perform wireless restores and safer wired backups (because the mac doesn’t locally mount the disk). We then keep Time Machine backup databases of both my dad’s iMac and (once 10.5 is on her MacBook Pro) my mom’s MacBook Pro on the same disk so as to need less active hard drives around the house.

I hope your Time Machine setups are working well, enjoy, Alex.