Time machine - how does it work?

Discussion in 'Mac Pro' started by msmth928, Jun 18, 2009.

  1. msmth928 macrumors regular

    Jun 3, 2009
    After receiving advice from you guys, I think I will opt to go with:

    Disk 1 - OS and my Files
    Disk 2 - Time Machine to back up Disk 1
    Disk 3 - smaller, slower disk for non important files such as trailer downloads etc

    I have a question about time machine though.... how does it work? :eek:

    If I set time machine to back up my disk one, and say I install a program that messes things up a bit (and simply deleting it from my apps doesn't fix the problem) can I 'just' revert the OS files? Or will it revert all of my own saved files, such as photos too?

    Or is it more like a snapshot, where I can pop in and take the files I want from a particular time and copy them to my current state of HD? Which is great for copies of a file you're working on but how would that help when the os is playing up?

    And finally, if my main HD dies, can I simply copy my personal (not OS) files onto the new disk? (I guess so but just checking) so for eg, if I wipe disk 1 and install snow leopard on it when it comes out, I could simply fetch my personal files from disk two?

    Thanks in advance! :apple:
  2. kbonnel macrumors 6502

    Mar 1, 2004
    In a nice place..


    First let me say that I am no expert in TM, but I have used it some to restore files as well as restore my MBP. TM, from my understanding, will perform a full backup of your system the first time it runs, and then will perform smaller incremental backups till the next full backup. It does keep track of every single backup that is run, and if you enter TM you can specifically go through each backup to see the files it grabbed. You can also add directories / disks to the exclusion list so that they are not backed up (such as downloads, etc).

    For your first question, and possibly second, (just restoring the OS files & snapshot), I don't believe it works that way. I don't believe it is a snapshot type of backup, where you can restore the system to a previous TM backup and then move forward. It is more for, from my experience, allowing the user the ability to retrieve a file they might have deleted, or a previous form of the file. (I have done this quite bit with my research papers, where I make so many changes to the current draft and need to look at an older draft for reference :) ). Also note, if you install a program, those files will then be backed up via TM. If you delete it, it will not remove them from the TM backup. Instead, all new TM backups will not show that file, and if you wanted to retrieve it, you would have to go back to the last time it was on the system and backed up. Hopefully this answered the first 2 questions :) On my system, TM runs every hour and backs up changes that occurred during that time.

    "And finally, if my main HD dies, can I simply copy my personal (not OS) files onto the new disk? (I guess so but just checking) so for eg, if I wipe disk 1 and install snow leopard on it when it comes out, I could simply fetch my personal files from disk two?"

    This is a good question; I have never done this before. I have used TM to restore the same system from scratch, but have never tried to retrieve files on a freshly installed system. I would think you could, otherwise the backup becomes useless if you can't get to it.

    I did some playing around, and I am pretty sure you can do this. The TM looks like a simple disk share, which you can open it up and mount the sparcebundle file. From there, you can grab what you want. What I don't know is if you can use the TM functionality to grab the files, or if you have to use the finder to do it. (And I am referring to doing this if you were on a new system, that didn't create the TM backup)

    I personally utilize TM and additional backup functionality for my important files (pictures, documents, etc). I do major backups of these once a week using rsync to my NAS.

    Hope this helps some. I am sure there are folks out there with much more TM experience and understanding than me, so I assume they will chime in.
  3. Tesselator macrumors 601


    Jan 9, 2008
    That's what I thought too but bozz says it IS actually a full backup solution that you can restore from. I've never used it so I dunno anything about it first hand. :)

  4. Loa macrumors 68000


    May 5, 2003

    I'm not a fan of TM at all: to many things happen that you have no control over, and you lack a lot of fine tuned control over the types of back-ups that are made.

    On the other hand, I've had the HD of my iMac die on me last april, and TM saved me. Before it completely died, I managed to boot "semi-normally" (after something like 25-30 failed boot-ups) and plugged in an external HD. I simply asked TM to do a complete back-up of everything.

    Well, when the iMac came back from Apple with a brand new (and empty) HD, I used that TM back-up to restore everything. And it worked.

    On the other hand, replacing an OS using TM, while running the computer with that same OS, could prove problematic. You could always boot-up using a Mac OS DVD, but then the TM interface would not be available. The backed-up system folder would be on your TM drive though, and it would be easy to access it manually.

    All in all, I'm switching to CCC as a back-up tool, but TM (with all its less-useful bells and whistles) works too...


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