Time Machine. Need help understand it.

HLdan

macrumors 603
Original poster
Aug 22, 2007
6,396
0
Sorry if this has been brought up but I can't find it.
How does Time Machine actually work. Does it actually clone my hard drive in my iMac? So for example if my iMac has 50GB of files installed such as music, photos and so on does Time Machine transfer all of the same files to my external drive? Some one explain please because I want to see how useful it will be in Leopard.
 

Father Jack

macrumors 68020
Jan 1, 2007
2,481
1
Ireland
As far as i know, Time machine initially make a complete copy of your machine, then it backs up any changes hourly .... :eek:
(I hope that's correct)
 

overanalyzer

macrumors 6502a
Sep 7, 2007
909
0
Boston, MA USA
I believe that by default, it starts with a full backup of your entire system, and updates that every hour, keeping hourly, then daily, then weekly backups as long as possible until the backup drive is full. You can also specify to exclude files or directories, if you don't want Leopard to automatically backup everything.

As a side note, Time Machine uses multi file linking to have every backup *appear* to contain every file, so that unlike most differential backups, you can restore completely from any one backup. But since the files are multi linked instead of actually copied, they don't take any extra disk space. As I understand it, this is why the drive needs to be HFS+ formatted.

EDIT: Actually, there is a pretty good amount of information on the Leopard site at this point: http://www.apple.com/macosx/features/timemachine.html
 

nuclearwinter

macrumors regular
Nov 3, 2003
208
0
Milky Way
If you REALLY want to know how it works...

... go here. It's a great in-depth article on exactly how Time Machine works without a file system like ZFS. It's quite interesting the way it handles multiple versions of files, though it gets a bit technical at some points.
 

Reflow

macrumors 68000
Mar 30, 2005
1,567
0
NJ/PHL
Will time machine work on network drives. I says that usb/firewire drives but nothing about NAS
 

Nabooly

macrumors 6502a
Aug 28, 2007
851
2
Im really looking forward to Time machine as i just deleted a 30 Gb folder that had lots of important stuff, yesterday. :( I recovered 28 gigs though so thats good, but it took a while and some of the files are corrupted.


^^
That was on a PC, but still the whole concept is great! :)
 

jaw04005

macrumors 601
Aug 19, 2003
4,369
15
AR
Will time machine work on network drives. I says that usb/firewire drives but nothing about NAS
Steve Jobs in one of the WWDC keynotes (not sure whether it was 06 or 07) mentioned that it worked over AirPort Extreme's AirDisk. Therefore, I would assume there would be some way to make it work with an external NAS.

I know Microsoft's product manager for Windows Home Server also mentioned publicly that it would be also be compatible with Time Machine.

Although this feature could have been dropped. I'll try to find the link.

It was previously mentioned on the Time Machine Web site before the latest update:

"With a hard disk connected to your AirPort Extreme Base Station, all the Macs in your house can use Time Machine to back up wirelessly. Simply select your AirPort Disk as the backup disk for each computer and the whole family can enjoy the benefits of Time Machine."

http://64.233.167.104/search?q=cach...ne.html+time+machine&hl=en&ct=clnk&cd=4&gl=us

But all references to using an AirPort Extreme have been removed on current pages.

Great Q&A: http://www.tuaw.com/2007/10/19/leopard-spotlight-preparing-for-time-machine/

In the WWDC build, Time Machine allowed you to backup to network disks if they were already mounted. This is from personal experience.
 

theman

macrumors 6502a
Jul 26, 2007
738
0
... go here. It's a great in-depth article on exactly how Time Machine works without a file system like ZFS. It's quite interesting the way it handles multiple versions of files, though it gets a bit technical at some points.

that article says,

"Every day, it drops the previous day's hourly backups. Every week it drops the previous week's daily backups. That maintains a complete, extensive set of backups that balance out the demands for backup frequency versus disk space."

what exactly does that mean? it deletes backups it has already made?
 

emptyCup

macrumors 65816
Jan 5, 2005
1,482
1
what exactly does that mean? it deletes backups it has already made?
That's right. It only stores hourly backups for the previous 24 hours, daily backups for the last month, and weekly backups for all days after the last month (until it runs out of space). It's a compromise between storage space and safety.

overanalyzer's link is very good. Learn more there.
 

0098386

Suspended
Jan 18, 2005
21,576
2,909
Is any compression involved? I've got a 60gb external drive that hasn't been used in a very long time. Would love to give it a home with Time Machine but I doubt it'll hold all my docs. My iPhoto library alone is now 11gb :eek:
 

emptyCup

macrumors 65816
Jan 5, 2005
1,482
1
Is any compression involved? I've got a 60gb external drive that hasn't been used in a very long time. Would love to give it a home with Time Machine but I doubt it'll hold all my docs. My iPhoto library alone is now 11gb :eek:
No compression is involved. However, after the first full backup, only changes are stored. You can use the old drive if your current machine has less than 60 GB on it.
 

wordmunger

macrumors 603
Sep 3, 2003
5,124
2
North Carolina
You can also specify which files to back up. For example, if your iPhoto library doesn't change that much, you could manually back it up on DVDs, and not have Time Machine back it up at all, reserving Time Machine for your other documents.
 

dukebound85

macrumors P6
Jul 17, 2005
18,136
1,450
5045 feet above sea level
can you make it so you can have stuff on the external that isnt on my laptop. for instance i have time machine enabled but want to keep all of my videos on the external but not my laptop. is this possible. i didnt by an external soley for backup....
 

overanalyzer

macrumors 6502a
Sep 7, 2007
909
0
Boston, MA USA
can you make it so you can have stuff on the external that isnt on my laptop. for instance i have time machine enabled but want to keep all of my videos on the external but not my laptop. is this possible. i didnt by an external soley for backup....
The easiest way is just to partition the drive. That's how I have mine set up and it works quite well. And with Leopard's new ability to dynamically resize partitions, it's easy to adjust the split if needed.
 

ZiggyPastorius

macrumors 68040
Sep 16, 2007
3,142
1
Berklee College of Music
So say I'm on a Macbook, 80GB Hard drive. Most of what would actually be on the laptop harddrive is programs and text documents. I plan on getting a 350-500GB, more likely 500GB, but it's not really for backup. I can partition the external itself so that I can dedicate 150GB or something like that to time machine back-up, and the rest to however I want? If that's true, then it won't move into my other partitions if I run out of space? I assume not, but just checking. And with my setup like that, I'm obviously not going to want to keep an external connected all the time. If I don't have it there when Time Machine goes to back up, what is it going to do? Is it going to give me some annoying message about setting up a new space for Time Machine? Or will it just ignore the backup until I reconnect it? If anyone knows the easiest way I can do all this without annoying problems, it'd be appreciated.
 

overanalyzer

macrumors 6502a
Sep 7, 2007
909
0
Boston, MA USA
So say I'm on a Macbook, 80GB Hard drive. Most of what would actually be on the laptop harddrive is programs and text documents. I plan on getting a 350-500GB, more likely 500GB, but it's not really for backup. I can partition the external itself so that I can dedicate 150GB or something like that to time machine back-up, and the rest to however I want? If that's true, then it won't move into my other partitions if I run out of space? I assume not, but just checking. And with my setup like that, I'm obviously not going to want to keep an external connected all the time. If I don't have it there when Time Machine goes to back up, what is it going to do? Is it going to give me some annoying message about setting up a new space for Time Machine? Or will it just ignore the backup until I reconnect it? If anyone knows the easiest way I can do all this without annoying problems, it'd be appreciated.
No, it'll stick to where you tell it :)

If the drive isn't connected when it wants to back up, it waits until you reconnect the drive and then immediately starts backing up. I tested this out myself.
 

tyr2

macrumors 6502a
May 6, 2006
801
83
Leeds, UK
So say I'm on a Macbook, 80GB Hard drive. Most of what would actually be on the laptop harddrive is programs and text documents. I plan on getting a 350-500GB, more likely 500GB, but it's not really for backup. I can partition the external itself so that I can dedicate 150GB or something like that to time machine back-up, and the rest to however I want? If that's true, then it won't move into my other partitions if I run out of space? I assume not, but just checking..
Yes partitioning it into it's own space is a good idea otherwise it will eventually consume all the free space on the drive as it keeps as many old backups as you've got space for. If you constrain it to a partition it will start to clear old backups when it runs out of space, for which you should get a warning asking you to confirm.
 

ravenvii

macrumors 604
Mar 17, 2004
7,584
490
Melenkurion Skyweir
One thing I'm wondering about is,

If you install Leopard, enable Time Machine and have it back up like normal, etc. Then after, say, 6 months or something, you decide to erase and reinstall leopard just cuz. Will the backups made during the 6 months still be accessible with the new installation of Leopard?
 

overanalyzer

macrumors 6502a
Sep 7, 2007
909
0
Boston, MA USA
One thing I'm wondering about is,

If you install Leopard, enable Time Machine and have it back up like normal, etc. Then after, say, 6 months or something, you decide to erase and reinstall leopard just cuz. Will the backups made during the 6 months still be accessible with the new installation of Leopard?
Yes, in fact I had opportunity to test that as well. In addition to being able to directly access the backed up files from the drive, you can also use the Migration Assistant tool or Time Machine to recover files from the backup, and you can also set that drive as being for Time Machine again and it'll happily keep the old backups (space allowing) and continue backing up your new installation.
 

QuarterSwede

macrumors G3
Oct 1, 2005
9,236
1,245
Colorado Springs, CO
Yes, in fact I had opportunity to test that as well. In addition to being able to directly access the backed up files from the drive, you can also use the Migration Assistant tool or Time Machine to recover files from the backup, and you can also set that drive as being for Time Machine again and it'll happily keep the old backups (space allowing) and continue backing up your new installation.
Yep, when my hard drive finally fails I plan on doing exactly that. Time Machine really is one of the best features of OS X and is how backing up should have been in the beginning.

Time Machine backups up everything to Backups.backupdb > Computer name > Date & id#

Click on a specific Date & id# folder and you can browser what is backed up by folder just like on your Mac. This is great if you need something off of it and you only have a PC available.

If you have another computer backing up to the same partition on the backup drive it'll create a folder in Backups.backupdb for that computer name as well. My wife and I have both of our Macs backed up to a 320 GB WD My Book and it works wonderfully. This is also with an 80Gb partition that has my Tiger clone on it (for when was installing Leopard). In fact, now that I'm done with the installation, there is no reason to keep it.
 

ZiggyPastorius

macrumors 68040
Sep 16, 2007
3,142
1
Berklee College of Music
No, it'll stick to where you tell it :)

If the drive isn't connected when it wants to back up, it waits until you reconnect the drive and then immediately starts backing up. I tested this out myself.
Phew, that's good. I think what I'll do is partition a 150GB and 170GB partition (if I get a 320GB EHD) or a 150GB and 350GB partition (if I get the 500GB), and use the 150 for Time Machine, which should be more than enough, considering I'll probably never use up more than 20-30 gigs. I plan on keeping all my music/music projects/et cetera on the external, anyways.

One thing I am wondering, though, and I know this isn't the correct thread, but I'll ask, and if someone wants to redirect me to someplace better to ask instead of answering, feel free...

What is the real difference between desktop and portable EHD's? Is it simply size? Because I will be taking my EHD with me pretty much everywhere I take my macbook, and I don't want to pay, say $250 for a 320GB portable EHD when I can buy a 500GB desktop EHD for $150. If it's a little bit bigger and that's it, then I have no problems. Is there something else that would fore some reason disallow me to take a "Desktop," EHD with my "portably?"
 

dukebound85

macrumors P6
Jul 17, 2005
18,136
1,450
5045 feet above sea level
Phew, that's good. I think what I'll do is partition a 150GB and 170GB partition (if I get a 320GB EHD) or a 150GB and 350GB partition (if I get the 500GB), and use the 150 for Time Machine, which should be more than enough, considering I'll probably never use up more than 20-30 gigs. I plan on keeping all my music/music projects/et cetera on the external, anyways.

One thing I am wondering, though, and I know this isn't the correct thread, but I'll ask, and if someone wants to redirect me to someplace better to ask instead of answering, feel free...

What is the real difference between desktop and portable EHD's? Is it simply size? Because I will be taking my EHD with me pretty much everywhere I take my macbook, and I don't want to pay, say $250 for a 320GB portable EHD when I can buy a 500GB desktop EHD for $150. If it's a little bit bigger and that's it, then I have no problems. Is there something else that would fore some reason disallow me to take a "Desktop," EHD with my "portably?"
yea size. 3.5 vs 2.5. also the desktop external requires a power source while some portable external may only need a usb for power needs
 

overanalyzer

macrumors 6502a
Sep 7, 2007
909
0
Boston, MA USA
Phew, that's good. I think what I'll do is partition a 150GB and 170GB partition (if I get a 320GB EHD) or a 150GB and 350GB partition (if I get the 500GB), and use the 150 for Time Machine, which should be more than enough, considering I'll probably never use up more than 20-30 gigs. I plan on keeping all my music/music projects/et cetera on the external, anyways.
Just make sure your music/music projects/etc. aren't only stored on one drive. If you keep them on the external drive only and it fails, obviously you'll lose them. Same reason for backing up from the internal HD so you don't lose files if it fails. And of course ideally, you should also keep a backup of important files you wouldn't want to lose in a theft or fire/flood/etc. somewhere else.
 

ZiggyPastorius

macrumors 68040
Sep 16, 2007
3,142
1
Berklee College of Music
Heh, yeah, I catch you. Unfortunately, though, I don't have the money to buy another EHD, or the space to fit all my music (90GB+) on my internal and external, which is why I'm buying the external, along with my music projects I create. Plus, I'm no foreigner to losing data. 4 days ago, I accidentally deleted my Windows while installing Linux (formatted the wrong partition by accident) and lost all my music and photos and like 400+ compositions in Finale. Fortunately, I'm not phased too much and am just trying to get it all back now, not a problem :p
 

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