How Time Machine works when offline?

[LeandrodaFL]

For the experts...I havent got an answer for this, so Im posting again. This time Im listing all possible outcomes, so all you have to do is pick one answer for the 2 different scenarios....(running snow leopard)

So, question number 1:

I turn on Time Machine for the first time. After doing the first backup, I disconnect the external Hard drive, but I leave Time Machine on. After 3 months, I connect the hard drive again. What happens?

a) Time Machine recognizes the drive and then updates the backup, by adding 1 more version of the changes since last time a backup was performed.

b) Time Machine recognizes the drive and then updates the backup, by adding ALL HOURLY VERSIONS of the changes since last time a backup was performed.


Question 2:

I turn on Time Machine for the first time. After doing the first backup, I turn OFF Time Machine, but I leave the external Hard drive ON. After 3 months, I turn on Time Machine again. What happens?

a) Time Machine will recognize both the drive and the already made backup and will then simply add 1 more version of the changes since last time a backup was performed.

b) Time Machine will see itself as turning on for the first time, and even tough a Time Machine backup is already on the hard drive, Time Machine will ignore it, and perform a FULL system backup ALL OVER AGAIN to the hard disk.


There you go folks, I hope to get an answer this time and therefore understand more about Mac OS. thanks for the help!

 

[Mal]

Barring any other extenuating circumstances, Time Machine will behave the same in both cases. Which one will depend on whether you're on 10.5, 10.6 or 10.7.

In 10.5 or 10.6, it will update that backup with a single new version from that date. It will not contain any previous hourly backups, as it will not have made any.

In 10.7, it will update the backup using data from Versions, which may contain additional "hourly" backups, though not one from each hour of the 3 months between backups. Thus, the actual number of backups will fluctuate depending on your usage.

jW

 

[26139]

Yep

What the previous poster said.

If you want incremental, hourly backups, you need to leave time machine running and connected.

I have mine turned off, with a hard drive attached to my AEBS. Every night I tell it to back up.

I have mostly daily backups now, with no need to plug/unplug.

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So A is the likely answer in both scenarios.

 

[Winni]

For the experts...I havent got an answer for this, so Im posting again. This time Im listing all possible outcomes, so all you have to do is pick one answer for the 2 different scenarios....(running snow leopard)

So, question number 1:

I turn on Time Machine for the first time. After doing the first backup, I disconnect the external Hard drive, but I leave Time Machine on. After 3 months, I connect the hard drive again. What happens?

a) Time Machine recognizes the drive and then updates the backup, by adding 1 more version of the changes since last time a backup was performed.

b) Time Machine recognizes the drive and then updates the backup, by adding ALL HOURLY VERSIONS of the changes since last time a backup was performed.


Question 2:

I turn on Time Machine for the first time. After doing the first backup, I turn OFF Time Machine, but I leave the external Hard drive ON. After 3 months, I turn on Time Machine again. What happens?

a) Time Machine will recognize both the drive and the already made backup and will then simply add 1 more version of the changes since last time a backup was performed.

b) Time Machine will see itself as turning on for the first time, and even tough a Time Machine backup is already on the hard drive, Time Machine will ignore it, and perform a FULL system backup ALL OVER AGAIN to the hard disk.


There you go folks, I hope to get an answer this time and therefore understand more about Mac OS. thanks for the help!

a) is the only logical answer for both cases.

What makes you think that the b) answers are even a possibility?

Where would Time Machine store the hourly backups when there is no backup drive online?

And why would Time Machine erase an already configured backup disk just because the Time Machine service/daemon was temporarily turned off?

 

[LeandrodaFL]

a) is the only logical answer for both cases.

What makes you think that the b) answers are even a possibility?

Where would Time Machine store the hourly backups when there is no backup drive online?

And why would Time Machine erase an already configured backup disk just because the Time Machine service/daemon was temporarily turned off?

-Because thats how some backup software behaves

-Local hard drive, thats how some backup software behaves

-Not erase, simply start from scratch