Does Time Machine Compress My Data?

Can I use a 160Gb external drive to back up more than 160Gb of data on my computer? Does Time Machine compress anything, or would I have to decide what to back up and what not to?

Time Machine doesn't compress anything.  It is better to have a destination Time Machine hard drive that is twice the capacity of the source.  Compression can lead to data corruption, or unrecoverability because the data compression engine may not have a compatible decompressor at the time of recovery.

Similar Messages

  • HT201250 Does time machine compress the data in backup?

    I have got to replace my internal hard drive so have to back up just everything to an ext drive.
    When I use 'time machine' to back up to an external disk, does that disk have to be larger than the file size on my iMac?
    Does Time machine compress the data?( eg will 1TB fit on a 500 gig external drive?)
    Thanks

    No, Time Machine doesn't compress the data. I recently started a new TIme Machine backup, and the first backup required the same amount of space as it was backing up (actually a little bit more during the backup process).

  • HT201250 How does Time Machine allocate backup data.

    I have over 150GB to back up with time machine and only 256GB HD to use, does Time Machine back up all files each time or only files updated after the last backup?

    Time Machine first makes a full backup, and then, it makes incremental backups backing up only the files that have changed since the last backup. When the Time Machine drive gets full, Time Machine will start deleting old backups in order to be able to make new backups. If you want more information about Time Machine, see > http://pondini.org

  • Does time machine back up data for all users on a shared computer?

    If I set up Time Machine backups from my own login, does this mean that all data on the computer is backed up, including that for other users?

    Good question.. yes, it should.
    http://pondini.org/TM/2.html

  • Does Time Machine use a differential/delta file compression when copying files ?

    Hello,
    I would like to use Time Machine to backup to a MacBook Air but that computer is using a Virtual Machines store in a single file of 50 GBytes.
    Once the initial backup will be done, does Time Machine will only copy the changes in this large file or will everyday copy the full 50 Bytes?
    In other word does Time Machine use a differential/dela file compression algorithm (like un rsync)?
    If it is not yet the case, can you please file for me an application request to the development team internally?
    If others are also interested in such a feature, you’re welcome to vote for it.
    Kind regards,
    Olivier

    Ok, it looks like the current version of Time Machine cannot handle efficiently in network terms large files like Virtual Machine files and this a real issue today.
    Is anybody here able to file an official feature request to Apple to be able to use Time Machine efficiently also with large files (let's stay > 5 GBytes) ?
    I should propably mean using a differential compression algorythm over the network like the examples below:
    http://rsync.samba.org/tech_report/tech_report.html
    http://en.wikipedia.org/wiki/Remote_Differential_Compression

  • How Does Time Machine Help If... iCal Data Lost?

    Hi,
    How does Time Machine help if, say, your iCal database gets messed up? Or, how does it help if you accidentally delete all your playlists from iTunes? I'd be interested to know.

    That's a very good question (although probably better directed at Apple than us). Because Time Machine is new and Apple's in house programs handle data in different ways, there are a range of different means of recovering data for different applications. Not very user friendly and iCal is one of the least user friendly ones.
    As an experiment, because I don't make much use of iCal and have no real idea how it works, I tried to find out how to restore its data. Starting with working with the application: nope, not TM aware at present. OK, where does it restore its data? Next step Spotlight where, as it happens, the obvious search "Calendars" brings up a folder in ~/Library labelled that with a whole lot of mysterious stuff in it. I'm pretty sure that restoring that folder would do the trick. No doubt, if you could figure out which Calendar belongs to what in the above folder you could restore a single calendar that was causing problems. Still, Apple's clearly got some work to do to make this more transparent. Roll on iCal4!
    (By the way Mail also restores from within the program).

  • Does time machine back up the data in the PC part of my intel MacBook?

    I'm backing up my MacBook to an external hadr drive using Time Machine in the apple part of my partioned MacBook.
    Does time machine back up the data in the PC part of my intel MacBook at the same time or do I have to do a separate backup for it? Does it have to be on a different external hard drive?

    Franklin Osgood wrote:
    I'm backing up my MacBook to an external hadr drive using Time Machine in the apple part of my partioned MacBook.
    Does time machine back up the data in the PC part of my intel MacBook at the same time or do I have to do a separate backup for it? Does it have to be on a different external hard drive?
    TM only backs up the BSD portion of your HD.
    If you partition your external HD you can have a FAT32 or NTFS partition for Winders and another for HFS+.
    Naturally if you choose to repartition the drive, you should backup everything on it or you may lose it.

  • HT201250 What does time Machine back-up?

    I would like to use Time Machine as a back-up on an external USB hard drive.  However, I am not sure what it actually backs up.  I want it to back up only the main Mac hard drive and not all the files and folders on the external drive which I will also use as the destination for the TimeMachine back-up.  Is there a way to do this or does Time Machine only back-up the main MacHD and not connected "data" drives like the external one I will use for TimeMachine.  Also, how do I make a bootable "rescue" drive or disk if my hard drive fails and I want to install a new one?  Will a "rescue USB flash drive" -- bootable  with the operating system (Mountain Lion) in it -- in conjunction with Time Machine on the external drive restore a new hard drive (MacHD) to what was on the old one?  Finally, how does one make a rescue (bootable) USB flash drive with OSX 10.8.2 on it?
    Mike

    Try going system preferences>time machine.select disk>highlight the disk, click use for back up (make sure the padlock is unlocked.  If this has already been done there might be a problem with the disk.  Go to utililites>disk utilities highlight the disk click verify disk.

  • Does Time Machine Compare/Verify Files?

    I have typically performed manual backups, and have no experience with Time Machine.
    Does Time Machine COMPARE / VERIFY that the backup files match the originals?
    I used to use Retrospect for Archive/Backup, which logged an alert if there was any mis-match in the backup process. Now I tend to backup files simply using Drag/Drop copying to redundant external storage devices. I have recently encountered errors in this process when backing up larger amounts of data. Hopefully this will not occur using TIme Machine. 
    What does Time Machine do if there is an error in the backup process?
    Is Time Machine the most reliable solution for Archive/Backup?
    thanks

    Time Machine logs to the system.log as process com.apple.backupd, which you can access via Appplications -> Utilities -> Console
    Carbon Copy Cloner logs to a CCC.log which you can access from within CCC, or via Applications -> Utilities -> Console.
    CCC will popup and error if there is backup problem.
    SuperDuper has its own built-in log, that you access via SuperDuper.
    SuperDuper will popup an error if there is a backup problem.
    CrashPlan has a /Library/Logs/CrashPlan/ directory with backup logs.
    CrashPlan can send you an email if there is a backup problem. Even better, it will tell you if a backup has not completed within the last 3 days.  I find that very nice in that automatic backups that stop and you haven't noticed it, is more annoying than not having a backup verification.
    I also remember Retrospect.  And the verify taking longer than the backup is a good excuse to just make another backup using a different utility and media destination.

  • Does Time Machine only work with external HDD's and Networks?

    I have a Mac Mini that I just replaced the optical drive with a hard drive. This second HDD is formated into two partitions, with one of them being for my Time Machine backups, the other a media scratch drive.
    When I try to choose this volume in setting up Time Machine, I get an error message that says, +"Are you sure you want to back up to the same disk your original data is on?"+ The message goes on to explain that +"the volume you have chosen for storing backups is on the same disk as the volume containing your data... you should back up to a volume on a different disk."+
    The volume that I have selected IS on a different disk than my start-up system drive and the data to be backed up IS NOT on the same disk as the disk storing the backups. System Profiler defines my startup HDD as "BSD Name: disk0" and my second HDD as "disk1," with the two partitions "disk1s2" and "disk1s3." Mount Point for the start-up HDD is "/" and the two partitions on the second HDD are "/Volumes/Scratch Disk" and /Volumes/Time Machine." These two volumes show up as options when I "Choose Backup Disk" in Time Machine, but not the Mini's startup HDD.
    Does Time Machine allow the use of second internal HDD? I have an external HDD, but it has a clone of my start-up drive on it. Thanks for any help.

    Chris, excluding the other volume could certainly be the issue since the two options that I'm given for a backup volume are both on the same hard disk. The start-up system HDD is not listed. Maybe the message is referring to this, rather than to the start-up disk.
    Not until after I selected "use this volume anyway," did I get to the "Option" screen to exclude items from the backup. When I selected "+" I was surprised to find the other volume, Scratch Disk, listed along with the start-up HDD as being included in the backup routine. So I selected Scratch Disk as one of the items to exclude.
    As V.K. mentions, the cautionary message is rather vague as to what exactly it is referring to. Thanks.

  • Does Time Machine backup iCal?

    I had a problem with some lost todo items the other day and checked to see if I could see a backup calendar as a quick way to solve the problem. If I am on address book and enter time machine, I see backups of my old address books and if I am on mail, I get all my old mail messages on the screen (though the todo item is grayed out), but if I am on iCal, I simply get the Finder window.
    Does Time Machine backup iCal or do I need to do a manual backup and then let Time Machine backup that file from finder?

    Since reading some of the first messages, I have been backing up my calendar each week and putting the backup file in my documents folder. I know that file is backed up, so I assume in case of a major problem, I could pull it from Time Machine and restore the data.
    Out of curiosity, though, I explored the folders in my library/calendar path and found a number of folders, each containing a file that was dated either today or within the last few days. I assume each folder is for a different calendar and that in case of total disaster, I could restore these from Time Machine.
    My question at this point: When I export the calendar from iCal, if the All Calendars option is checked, am I safe in concluding each of the separate calendars would be there? If I accidentally had one calendar highlighted, would only that calendar be backed up?

  • Does Time Machine really restore all files of app?

    Hi mac people,
    I have done a clean install, then i don't want use migration assistant to move back things, but when i move back garageband 6.0.5, i open it, then i realise that only app is been restore but all the loops and audio is not, then i search online found that i have to move those things by my own,
    So this problem make me wondering does time machine really fully restore?
    I also wondering how about other apps or files do they really all been restore even they SEEN like no problems?
    Thanks for helping !!!!!

    then i realise that only app is been restore but all the loops and audio is not, then i search online found that i have to move those things by my own,
    If you want everything restored from Time Machine, don't use Migration Assistant but use Setup Assistant - migrate al files when you are first prompted to restore from Time Machine or another Mac, after a clean install.
    you can select what to restore - the settings, the libraries, the user data.
    Since you do not want to use the assistants - to restore Garageband 6.0.5 manually, you transfer all files and folders in the system library:
    /Library/Application Support/GarageBand/
    and the loops from
    /Library/Audio/Apple Loops/
    Your plug-ins from
    /Library/Audio/Plug-Ins/
    and the corresponding folders in your user library ~/Library/

  • Does Time Machine bundle backup sets when it deletes a month's daily sets?

    I'm asking this question to find out if I can delete the all but the last week in a month, each month, in order to extend the useful capacity of my backup drive.
    In some backup systems, a periodic "bundle" is made when previous sets are deleted, so for instance, the last backup of the month has the cumulative hourly changes of that month. In this way, transient files which appear and disappear within the month are retained in the monthly backup.
    Is this true of Time Machine? Exactly what does Time Machine do? Does it simply wipe out the daily sets and chose the last one to  be the "weekly backup?" Or something more sophisticated and useful?
    Thanks for any insight!

    I've devised a little experiment to discover Time Machine's behavior in this regard:
    On my Time Machine's backup schedule, August 27 corresponds with the end of a week. So, on August 26 at 9:15AM, I created the following [folder]/file structure:
    [Time Machine Test -Transient Roll-up]
       [Time Machine Test - 1. Hourly Transience
          A one hour lifetime file.rtf
       [Time Machine Test - 2. Daily Transience
          A one day lifetime file.rtf
       [Time Machine Test - 3. Weekly Transience
          A one week lifetime file.rtf
    At 10:10AM of that day I removed
      [Time Machine Test - 1. Hourly Transience
          A one hour lifetime file.rtf
    At 10:10 the next day, August 27, I removed
       [Time Machine Test - 2. Daily Transience
          A one day lifetime file.rtf
    On August 28 at 10:30AM, acheck today of the earliest backup of this structure reveals only the following:
    [Time Machine Test -Transient Roll-up]
       [Time Machine Test - 3. Weekly Transience
          A one week lifetime file.rtf
    I draw the conclusion that transient files within a time period are not subject to a "roll-up" mechanism that displays all changes after out-of-date files are deleted by Time Machine. Thus, for instance, any file that appeared and disappears during an hour will be lost in Time Machine's daily history. Similarly, files that only persist for a day will be lost in the weekly history. And, presumably, if one wanted to choose a week which represented an accumulation of transient changes during the month it would be impossible to do so.
    Even so, if one wants to manage only one backup volume, rather than accumulating a stack of them over the years, one might well think about selectively deleting all but one week per month in the earliest backups available, as the projected remaining time approaches less than a few weeks. BackupLoupe's Statistics gives an estimate of remaining time left for backups on a volume, and I would suggest using that as a forecast, unless others have experience to the contrary.
    Hope this is useful. It certainly is to me.

  • Does Time Machine backup open applications/files?

    I recently lost my calendars (in Entourage, Ical, Mobileme, etc.), and wanted to restore from a time machine backup.
    I tried to restore the Entourage identity from a day or two before only to see that the date in Time Machine for the file was way old.
    I suspected that because I leave the app open all the time, particularly all night when my backups run at 11 pm that the file never got backed up. Does this sound right?
    Ical, on the other hand (which is synched to mobile me and entourage), even though I rarely open it and use it, seemed to have the updated data.
    How does Time Machine deal with files that are in use?

    Entourage needs some special handling. I don't use it, so can't tell you exactly how to do it, but if you search this forum for Entourage you should find a post or two (by Kappy and/or Baltwo, I think) with good advice.

  • How far back does Time Machine back up?

    How far back does Time Machine back up? Thanks.

    Thanks Kappy and Tech Guy. I'll try and digest that info--it may take awhile!
    Just for info, I am using a Lacie d2 500 GB, presently it has used 263 of the 500.
    It is presently backed up until January 2010 which must be the date I hooked into Time Machine. I have a 1TB iOmega which I am thinking of using for the back up drive but feel the Lacie may be the better of the two so may leave it on.
    Thanks again. Cheers.

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