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

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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).

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).

How does time machine work when being used with a mac pro?

How does time machine work when backing up a mac pro?
Considering the fact that the mac pro can hold 8TB and a external (non NAS) hard drive can hold only 2TB does time machine only backup the OS disk.

macnewcomer22 wrote:
Considering the fact that the mac pro can hold 8TB and a external (non NAS) hard drive can hold only 2TB does time machine only backup the OS disk.
Time Machine will backup everything by default, on every disk in your Mac.
Choose System Preferences > Options to exclude items. You could exclude everything except your OS...but I'd think it is your data that's more important to you, if you have to make choices.
See...
http://discussions.apple.com/thread.jspa?threadID=1964018
While it's true you can store almost 8TB, how much do you think you'll actually store? If you have 1TB of data you want to store then a 2TB drive can do it. Also when your TM drive begins to get full it will begin deleting the oldest backups to make room.
You could also get a Drobo with 8 bays...
http://www.drobo.com/products/index.php
-mj

How does time machine back up separate but computers on the same drive

Thinking about hooking up a hard drive to APBS to use as a time machine for several macs /iPads, how does time machine keep these different devices separate? How does it keep the backup info separate? Thanks

APBS is usually called AEBS or Airport Extreme Base Station.
You can only do Time Machine to the newest one.. it is not supported on earlier models.
See http://pondini.org/TM/Home.html
Look for Gory details about airdisk.
Also it is going to help you to actually read how Time Machine works on network drives.
What you are asking has all the answers there.
http://pondini.org/TM/Works.html
ipads do not backup like macs.. there is no time machine.
ipads backup to itunes or to icloud. The backup to local itunes can then be backed up by TM to the disk you are using.
Please note even though Apple now says it works.. I have seen reports where the old problem has come back.. it works for 6-8weeks and then the backup corrupts itself and you have to start over.

How does Time Machine Handle separate Boot and User Volumes?

I recently installed an SSD and set it up as my boot drive, and I'm using another hard drive for my Home folder, if I ever run into a scenario that I need to restore my entire system, how will Time Machine handle it?
Will it restore my system back to the drives that they came off of?, in other words will my Boot volume be restored back to the SSD and my Home folder back to the hard drive, or will it restore everything back on the one disk it asks me to select before I click restore?

Michael Hoover wrote:
Ok, so if I tried to access a backup from booting with the Snow Leopard install disk I won't be able to select which volume I need to restore?
You would restore the OSX volume via the procedure in #14 of [Time Machine - Frequently Asked Questions|http://web.me.com/pondini/Time_Machine/FAQ.html] (or use the link in *User Tips* at the top of this forum).
You would restore the data-only volume separately, via the "Star Wars" display, per #15 in the FAQ.
I guess I would be better off doing incremental backups with Carbon Copy Cloner on 2 partitions on the same volume.
That would also take two separate operations to restore. (It would be a good idea to do such backups +*in addition+* to Time Machine backups, in case there's a problem with either disk drive or backup app, or a user error like erasing the wrong disk.)
Your scenario is actually quite unlikely; you'd rarely need to restore both volumes at once. If the SSD fails, you'd only need to restore it; if the HD fails, you'd only need to restore that.
It would get a bit more complicated if you get a new Mac, especially one with a single volume. That's one of the reasons it's a good idea to keep at least a minimal Admin account on the OSX volume.

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 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.

Time Machine: Mavericks backup date and time issues

Time Machine: Troubleshooting backup issues
re: http://support.apple.com/kb/HT3275
"Messages you may see after clicking the red "i" include:"
I am getting a message not listed at this page. My Time Machine fails to backup to my USB3 Passport External Drive with the error code:
"Time Machine couldn't complete the
backup to "2T PP".
The system date and time is incorrect."
I have the Date & Time preference set to:
"√ Set date and time automatically: Apple Americas/U.S. (time.apple.com)"
and it seems to be the correct time.
The Language & Region prefs, advanced, Dates tab is set to defaults but I cannot get TM to backup and the same error occurs.
How can I remedy this?

Because you have just loaded a new operating system and a complete backup occurs is my understanding.

How does time machine use the external disk space??

does time machine back up only the changed or new stuff or does it back up everything? does this mean that if on "day one" it backed up 600 gb worth of data, the next back up on "day 2" would be 600gb+a few more things, or would it be 600gb+600gb+the few more things? Does it back up "day one" in a whole package and "day two" in another package, or does it back up "day one", plus only the different things made from "day one" to "day two""?
similarly, does it keep stuff from the first back up ever, plus anything new or modified in the following back ups, then when it is full, does it let just the oldest files drop off? or does it drop off everything from the initial backup? that is, if I had 20mb of changes would it erase only 20mb of data to make the new data fit, or would it erase all 600gb from say "day one"?
thanks for the answer!
iMac, Mac OS X (10.6.8)
<Email Edited by Host>

See Pondini's TM FAQs for starters.

How retrieve Time Machine purple backups?

How retrieve Time Machine backups older than now? Am using Lion (10.7.2). In Time Machine, all my backups that are older than 'Now' have purple date/time stamps and bars, and no 'populated' finder-like window to enable access to my older-than-now backups. My TM backups are on a Drobo S.

Kadege wrote:
Hello Pondini, I've got the same problem, nearly all dates are purple, older than some days. This moves with the time, some days ago, 25-Dec was available, today it isn't (but 26-Dec is).
Do you mean the Dec 25 backup is no longer shown in the TimeLine at all? If so, either it's been deleted, or your backups are corrupt. If you didn't delete it, try to repair your backups, per #A5 in Time Machine - Troubleshooting.
Or, if you mean the Dec 25 backup is there, but is faded-out and you can't select it, that's because whatever's in your Finder window before you Enter Time Machine wasn't included in that particular backup -- select something else before entering Time Machine, or in the Finder sidebar once you're there. See #15A in Time Machine - Frequently Asked Questions for details, especially the pink box there.
When accessing the Backup on TimeCapsule via Finder directly, I can see the volume (500 GB) has left 19,37 GB free. I can see, too, all the backups, which are purple in Timemachine, exist (beginnin in July 2011 when I bought the computer).
Yes, eventually, Time Machine will fill all the empty space available to it. Before that, it will periodically "thin" your backups, per the schedule on the Time Machine Preferences window -- all but the first of the day are deleted after 24 hours; those are kept for a month, then reduced to one per week.
Once the drive gets near full, it will start deleting the oldest backup(s) to make room for new ones. Since you have your first backups, that hasn't started yet, but probably will before long.
including system-sofware and applications, which I don't backup by Timemachine.
That's usually not a good idea. It saves relatively little space (perhaps 10-20 GB), and no time (after the first backup), but it means you can't do a full system restore from those backups, or use them with either Setup Assistant or Migration Assistant to set up a new Mac, or to transfer your stuff if you have to erase or replace your internal HD. Once you get this sorted out, I'd strongly recommend removing those exclusions.
Message was edited by: Pondini

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.

HT201250 when does time machine back up?

I don't see an option to set when time machine backs up.

Time Machine makes hourly backups, and there's no way to change that without hacking. There's also no good reason to change it.
These statements are sheer nonsense. There are not only good reasons to change Time Machine's backup time frames (even if it's personal desire), but there are simple and effective means of doing it that do not adversely affect the system. Time Machine Editor is one of them, and has worked quite effectively for numerous people.
BTW, your link you use to support your argument was quite arguably not from the use of Time Machine Editor, as the user had numerous other and true "hacks" installed that were the root of numerous console errors and problems. I'm glad the developer chimed in and investigated, and pretty much invalidated your unfounded initial claim of "the mess he created" with his program. Libel is a pretty outrageous practice.

How does Time Machine handle multiple profiles?

Hello,
I have an IMac with 3 users, does time machine handle all users?
2 users are admins, but when i change users the time machine does not handle well the external drive.
Can you give some info in this matter.
Thanks
Nuno

It should work fine. All of my machines have multiple users. What problems are you having?

HT201250 How do I reduce the 'Backups' Data on my Macbook HD and how to reduce the parameters of Time Machine?

My Macbook Pro is using 320GB on "Backups" and Time Machine is using 640GB. It just seems ridiculous, considering I everything else only takes up 77GB combined. How to I get rid of a good chunk of it from Macbook HD and also how can I reduce the Time Machine parameters, maybe so it starts deleting back up data sooner?

If you run TM you don't really need local snapshots so if you need the disk space you can disable them in Terminal by copying & p;asting this command at the prompt
sudo tmutil disablelocal
Press return. You will be prompted for your password, it will be invisible.
To undo this, rerun it with "enablelocal" instead of "disablelocal".
In TM preferences you can choose to exclude items to the backup.
EDIT: See these helpful hints from Pondini.

HT201250 How does Time Machine allocate backup data.

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