***DISCLAIMER***
This thread/initial post was started shortly after TM was announced and intended to stop many threads with basically the same questions from popping up all over. I myself have not yet used TM so the questions/answers are based on the best data I had available at the time of last edit. I know that some of it has been proven wrong. If you have corrections you can PM me and I will do my best to correct errors as they are indicated. Thanks.
All answers are based on the information available here, here, and here (thanks applerocks).
TM = Time Machine
BUD = Backup drive
HD = Hard Drive
1) How does TM work?
Time machine performs an automatic daily backup of your HD to an external drive or server. Every day at a set time (default of midnight) the OS will create a snapshot of your HD. The OS only updates things that have changed since yesterday so the amount of space taken up is minimized. If you accidentally delete or change a file you did not intend to you can go back to a snapshot of your drive for any given day. Also as you make changes Leopard notifies TM and keeps track of only the changes to the files it will also periodically save the changed files to the backup drive, provided the backup is connected.
2) Won't Time Machine fill up my HD?
No. Time Machine performs a daily backup to a separate hard drive/storage device. It does not keep multiple copies of the files on your main HD. It keeps track of changes as you make them but does not create multiple copies of the file (think undo). It will periodically copy the changed file to your BUD if connected. I would guess that there is a finite buffer for recent changes if you are not working with the backup drive attached.
3) What if I create and delete a file between backups? Is there a way to recover that file?
This is still unclear. The Finder notifies TM of changes to a file. As you work (if you are connected to your BUD) the changed files are copied to the backup every so often. If you create and delete a file between writes to the BUD it is possible that the file is completely lost, or if you are not connected to your backup 24/7 and you create and delete a file in the time you are not connected it is possible that it is lost. At the end of the day the changes are coalesced into a final image for that day. Provided you are connected to your BUD and have the file existing long enough you should be OK.
4) Do I have to back up everything?
No. You can tell Time Machine which items to ignore during backup.
5) How is time machine different from other backup utilities?
TM keeps track of all the changes made on your drive in a given day and only backs up the changes. Utilizing this information it minimizes the space required for multiple backups and allows you to store further back in time. Most other utilities would require a daily, complete HD backup which would consume a lot of space, and a simple daily backup to the same location would not allow you to go back more than one day. TM allows you to go back and see exactly how your HD looked on any given day (provided you had the BUD connected that day). Given enough storage and minimal changes you may be able to go all the way back to the day you received your computer (for Leopard pre-installs) or the day you installed Leopard. TM creates a history of backups in one place so you can get a previous version of the file, where most other backup utilities would require multiple separate backups in order to walk back to a version of a file before the last backup. Some third party utilities, like Retrospect, already offer some of this functionality.
6) How far back can TM go?
Screenshots indicate that there are options for: Indefinitely, At least 1 month, At least 3 months, At least 6 months, At least 1 year. (Thanks shrimpdesign). It remains unknown if you can specify a maximum backup size or how that might be related to the duration of the backup.
7a) When Apple say backed up to a server do they just mean any network storage?
No, It must be a server or drive. It cannot just a remote drive on the network as 10.5 still sees the remote drive as a folder AFP mount.
7b) Can this backup be done to another Mac's HDD home server for my laptop)?
If the remote drive is partitioned and dedicated to TM, as in Target drive mode. So kinda, this is only true if it will handle partitions which I can't remember.
8) Can it be done over wifi / network, .mac?
wifi / network yes to a server, .mac no. (7a, 7b, & 8 provided by Fearless Leader)
9) Any idea of what the server has to be running for it to work with TM
"It will work with any non-bootable volume formatted in Apple’s HFS Extended format. That drive can be stowed inside a Mac Pro, attached on the end of a FireWire or USB cable, or even mounted on your desktop from elsewhere on your network. The one big catch is, the entire volume must be devoted to Time Machine—you can’t just stow Time Machine files inside a folder on a larger volume." link
10) Can you choose to permanently delete something?
Since the backup is done to an external drive and is intended as a backup there is no permanent delete until the time limit of the backup is reached. See #3 for how changes are tracked. If your BUD is not connected you may permanently lose any files created and deleted during this time period depending on how TM behaves when no BUD is present.
11) Will TM slow down everything because it constantly backs up?
Since it's only logging changes I would not expect it to slow down anything more than Spotlight did.
12a) What happens to my TM backup when i restore my system via recloning with super duper?
12b) What happens when I sync macs?
This one could go a couple of different ways. If the change tracking system is part of the main OS then you could end up in a situation where after cloning, only the files indicates as changed on the clone would get backed up which would mess with the timeline considerably. If the system somehow does a compare to the TM backup then all should be OK. You're first backup after cloning would be akin to a complete HD backup, and if you go back one day you would see the machine as it existed before cloning. At this point with the information available I cannot say how this will work. I'm sure Apple would prefer that you use TM for system restores in order to avoid this potential issue, you may also be able to use TM to make clones as well.
13) Is TM searchable?
In the demo at WWDC a search is shown using Address Book to find a particular contact that was deleted. It is unclear if or how this works in Finder. Can you search only a folder or the entire HD for a particular file? We don't know yet.
14) Can recover just some records for an application like Address Book to merge with any new data?
Yes or no, depending on how the application takes advantage of TM. In the demo Address Book is specifically used to find a deleted record and restore it, but it will be up to developers how they want to implement this feature in their app.
15) Can the Backup time interval be changed?
Everything I have seen indicates that it backs up once a day at a user specified time. I have not seen anything where they mention being able to back up more or less often than daily. Apple's website claims "Since backups are stored on your device by date" so it is probable that the backup interval cannot be shorter than a day.
16a) Does TM encrypt the backup data?
It can, but doesn't automatically.
16b) Is the TM backup accessible via the Finder?
yes, as long as A) Not encrypted, B) you can wade through the weird file structure.(16 a&b answered by Fearless Leader)
17) Does TM take over a backup volume?
Yes. However it will only take over one mounted volume, if you have a large disk that you would like to use for multiple backups you can partition it so each backup has it's own volume for TM.
18) How does TM work when no BUD is connected?
I have no idea. It is possible that anything done in these intervals is lost forever, it is also possible that Loepard keeps a rolling buffer of changes utilizing free HD space in the background to try and save as much information as possible until the BUD is reconnected.
19) Does TM makes bootable backups?
I'm going to guess that due to the way TM keeps track of how your HD looked through history I believe that the TM backup is some large database of files/folders. This would mean it's probably not bootable but the Leopard install CD has an option to restore a disk from TM BUD (confirmed by c-Row).
20) Will TM work with non-core image video cards/integrated graphics?
TM functionality has nothing to do with the video card in the system if Leopard supports the system TM will work however the animations and visual effects may be limited on some systems.
21) Does TM make mirrored, and other advanced RAID arrays for data recovery obsolete?
A RAID array set up for data recovery will not be made obsolete by TM. Since TM is not constantly writing to the BUD and it is unclear what happens when no BUD is connectd the RAID array is still one of the best methods for capturing everything in the event of a single HD failure.
22) Can TM restore system applications after and OS re-install?
TM can reinstall everything if you reinstalled the OS. (answer from Fearless Leader)
This thread/initial post was started shortly after TM was announced and intended to stop many threads with basically the same questions from popping up all over. I myself have not yet used TM so the questions/answers are based on the best data I had available at the time of last edit. I know that some of it has been proven wrong. If you have corrections you can PM me and I will do my best to correct errors as they are indicated. Thanks.
All answers are based on the information available here, here, and here (thanks applerocks).
TM = Time Machine
BUD = Backup drive
HD = Hard Drive
1) How does TM work?
Time machine performs an automatic daily backup of your HD to an external drive or server. Every day at a set time (default of midnight) the OS will create a snapshot of your HD. The OS only updates things that have changed since yesterday so the amount of space taken up is minimized. If you accidentally delete or change a file you did not intend to you can go back to a snapshot of your drive for any given day. Also as you make changes Leopard notifies TM and keeps track of only the changes to the files it will also periodically save the changed files to the backup drive, provided the backup is connected.
2) Won't Time Machine fill up my HD?
No. Time Machine performs a daily backup to a separate hard drive/storage device. It does not keep multiple copies of the files on your main HD. It keeps track of changes as you make them but does not create multiple copies of the file (think undo). It will periodically copy the changed file to your BUD if connected. I would guess that there is a finite buffer for recent changes if you are not working with the backup drive attached.
3) What if I create and delete a file between backups? Is there a way to recover that file?
This is still unclear. The Finder notifies TM of changes to a file. As you work (if you are connected to your BUD) the changed files are copied to the backup every so often. If you create and delete a file between writes to the BUD it is possible that the file is completely lost, or if you are not connected to your backup 24/7 and you create and delete a file in the time you are not connected it is possible that it is lost. At the end of the day the changes are coalesced into a final image for that day. Provided you are connected to your BUD and have the file existing long enough you should be OK.
4) Do I have to back up everything?
No. You can tell Time Machine which items to ignore during backup.
5) How is time machine different from other backup utilities?
TM keeps track of all the changes made on your drive in a given day and only backs up the changes. Utilizing this information it minimizes the space required for multiple backups and allows you to store further back in time. Most other utilities would require a daily, complete HD backup which would consume a lot of space, and a simple daily backup to the same location would not allow you to go back more than one day. TM allows you to go back and see exactly how your HD looked on any given day (provided you had the BUD connected that day). Given enough storage and minimal changes you may be able to go all the way back to the day you received your computer (for Leopard pre-installs) or the day you installed Leopard. TM creates a history of backups in one place so you can get a previous version of the file, where most other backup utilities would require multiple separate backups in order to walk back to a version of a file before the last backup. Some third party utilities, like Retrospect, already offer some of this functionality.
6) How far back can TM go?
Screenshots indicate that there are options for: Indefinitely, At least 1 month, At least 3 months, At least 6 months, At least 1 year. (Thanks shrimpdesign). It remains unknown if you can specify a maximum backup size or how that might be related to the duration of the backup.
7a) When Apple say backed up to a server do they just mean any network storage?
No, It must be a server or drive. It cannot just a remote drive on the network as 10.5 still sees the remote drive as a folder AFP mount.
7b) Can this backup be done to another Mac's HDD home server for my laptop)?
If the remote drive is partitioned and dedicated to TM, as in Target drive mode. So kinda, this is only true if it will handle partitions which I can't remember.
8) Can it be done over wifi / network, .mac?
wifi / network yes to a server, .mac no. (7a, 7b, & 8 provided by Fearless Leader)
9) Any idea of what the server has to be running for it to work with TM
"It will work with any non-bootable volume formatted in Apple’s HFS Extended format. That drive can be stowed inside a Mac Pro, attached on the end of a FireWire or USB cable, or even mounted on your desktop from elsewhere on your network. The one big catch is, the entire volume must be devoted to Time Machine—you can’t just stow Time Machine files inside a folder on a larger volume." link
10) Can you choose to permanently delete something?
Since the backup is done to an external drive and is intended as a backup there is no permanent delete until the time limit of the backup is reached. See #3 for how changes are tracked. If your BUD is not connected you may permanently lose any files created and deleted during this time period depending on how TM behaves when no BUD is present.
11) Will TM slow down everything because it constantly backs up?
Since it's only logging changes I would not expect it to slow down anything more than Spotlight did.
12a) What happens to my TM backup when i restore my system via recloning with super duper?
12b) What happens when I sync macs?
This one could go a couple of different ways. If the change tracking system is part of the main OS then you could end up in a situation where after cloning, only the files indicates as changed on the clone would get backed up which would mess with the timeline considerably. If the system somehow does a compare to the TM backup then all should be OK. You're first backup after cloning would be akin to a complete HD backup, and if you go back one day you would see the machine as it existed before cloning. At this point with the information available I cannot say how this will work. I'm sure Apple would prefer that you use TM for system restores in order to avoid this potential issue, you may also be able to use TM to make clones as well.
13) Is TM searchable?
In the demo at WWDC a search is shown using Address Book to find a particular contact that was deleted. It is unclear if or how this works in Finder. Can you search only a folder or the entire HD for a particular file? We don't know yet.
14) Can recover just some records for an application like Address Book to merge with any new data?
Yes or no, depending on how the application takes advantage of TM. In the demo Address Book is specifically used to find a deleted record and restore it, but it will be up to developers how they want to implement this feature in their app.
15) Can the Backup time interval be changed?
Everything I have seen indicates that it backs up once a day at a user specified time. I have not seen anything where they mention being able to back up more or less often than daily. Apple's website claims "Since backups are stored on your device by date" so it is probable that the backup interval cannot be shorter than a day.
16a) Does TM encrypt the backup data?
It can, but doesn't automatically.
16b) Is the TM backup accessible via the Finder?
yes, as long as A) Not encrypted, B) you can wade through the weird file structure.(16 a&b answered by Fearless Leader)
17) Does TM take over a backup volume?
Yes. However it will only take over one mounted volume, if you have a large disk that you would like to use for multiple backups you can partition it so each backup has it's own volume for TM.
18) How does TM work when no BUD is connected?
I have no idea. It is possible that anything done in these intervals is lost forever, it is also possible that Loepard keeps a rolling buffer of changes utilizing free HD space in the background to try and save as much information as possible until the BUD is reconnected.
19) Does TM makes bootable backups?
I'm going to guess that due to the way TM keeps track of how your HD looked through history I believe that the TM backup is some large database of files/folders. This would mean it's probably not bootable but the Leopard install CD has an option to restore a disk from TM BUD (confirmed by c-Row).
20) Will TM work with non-core image video cards/integrated graphics?
TM functionality has nothing to do with the video card in the system if Leopard supports the system TM will work however the animations and visual effects may be limited on some systems.
21) Does TM make mirrored, and other advanced RAID arrays for data recovery obsolete?
A RAID array set up for data recovery will not be made obsolete by TM. Since TM is not constantly writing to the BUD and it is unclear what happens when no BUD is connectd the RAID array is still one of the best methods for capturing everything in the event of a single HD failure.
22) Can TM restore system applications after and OS re-install?
TM can reinstall everything if you reinstalled the OS. (answer from Fearless Leader)
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