Does Time Machine forget files for my backup?

[lars666]

Hi everybody,

I just did a first backup from my system with Time Machine to my Time Capsule. The whole backup is 62 GB big - however, on my HDD 65 GB are used. No folders are excluded. Is there any explanation for this? Does Time Machine leaves out Safari caches or something like this automatically, does it compress the whole backup somehow - or do I have to worry that not everything is backed up correctly?

If anybody can give me an explanation, I would be grateful. Thanks in advance!

 

[soco]

Could the extra space be OS X itself?

 

[lars666]

Could the extra space be OS X itself?

I don't think so as you should be able to restore the complete system from the backup including the system (when booting from the OSX DVD and choosing the option - not migrating, but a full system restore).

 

[johnfkitchen]

Good question.

Not everything is backed up. Time Machine excludes stuff that would not be needed in a recovery situation.

James Pond's excellent website explains this and pretty much everything you'd ever need to know about Time Machine (and then some).

Take a look at this page

http://web.me.com/pondini/Time_Machine/2.html

"It will back-up your entire system (OSX, configuration, applications, user data, settings, preferences, etc. (less most system work files, caches, logs, trash, etc.), unless you specifically exclude things (see question #10 and/or question #11)."

It also doesn't back up the file used to store the RAM contents when a Mac laptop battery approaches zero charge

 

[lars666]

Thanks for the answer and the link. One thing I forgot to mention: It's not that Time Machine excluded the missing 3 GB from the start, as least not visually: It showed that it will back up the full 65 GB, but already quitted before the blue bar was completely 100% full up to the 65 GB. However, the backup was successful. (Or at least said it was.)

I already discovered this on past occasions - that not really everything is backuped. I think it should work fine and that there is an explanation for this, it's just that I one got problems with TM and now am a little paranoid ...