Serious Bug?: "Do not back up" forgets items that disappear temporarily
I have one of those Mac Mini that shipped with the flakey Seagate hard drives. After 20 months, mine failed this morning. Time Machine saved all my data and I was able to restore to a new drive. In so doing, I discovered what I believe is a bug in the Time Machine design. I had several folders marked in "Do not back up". Example: ~/Music/iTunes/iTunes Music/Podcasts. I don't want to back this up because podcasts are disposable, temporary files that take up much disk space. If I backed them up, a large portion of my backup drive would soon be wasted with useless old podcasts, severely limiting the "depth in time" of my important files. And I can always re-download a podcast from the producer's site if I really wanted to hear it again. Well, Time Machine was apparently obeying "Do not back up", because after I restored my system I found that I had no ~/Music/iTunes/iTunes Music/Podcasts folder. Works as expected. No problem because all the latest podcasts were on my iPod Shuffle. However, when I checked System Preferences > Time Machine > Options, I found that ~/Music/iTunes/iTunes Music/Podcasts was no longer in the "Do not back up" list. So, I had to manually re-add it to the list, or else it would start backing up podcasts. I'm not sure if I remember all the items that I had added to "Do not back up". I shouldn't have to remember and manually re-make the list. I believe this is a bug in the design. It could easily remember the paths, but it does not.
A bug that bites only after a hard drive failure may be tolerable, but it bites at other times too. I have another folder of temporary items which I often trash. I had put that folder in the "Do not back up" list at one time, but I just noticed that it was not in the list either. So, I re-added it to the list. Then, as an experiment, I deleted the folder. Then I opened System Preferences and observed my "Do not back up" list. Yup, it was no longer listed! I re-created the folder, re-opened System Preferences. Yup, it was still not listed.
So there is no way to permanently "Do not back up" a folder if it ever disappears temporarily.
But there's an even worse scenario, although I can't reproduce this because at this time I don't have the hardware available to connect two external drives at once. I've noticed that the same deletion from "Do not back up" happens with external drives. Think about it. Let's say you connect your Time Machine backup drive, and at the same time connect an Other external drive. Tell Time Machine to "Do not back up" the Other drive. OK, it won't back it up, until you disconnect it, but then it gets deleted from the list. Then, if you ever connect this Other drive and your Time Machine drive simultaneously, and backup time rolls around, and say this Other drive has 100 GB of movies on it (a common use for external drives), Time Machine is going to copy all ****** 100 GB to your backup drive! That will likely fill it up with movies you had backed up elsewhere, and cause older archives of important files from your internal drive to be deleted. And since Time Machine doesn't give you any view of how much space is being devoted to what items, if you hadn't read this post, you probably wouldn't even know what hit you. Arghhhhh!
Maybe it's not a bug. Could it be a secret feature for selling more 1000 GB Time Capsules?
A bug that bites only after a hard drive failure may be tolerable, but it bites at other times too. I have another folder of temporary items which I often trash. I had put that folder in the "Do not back up" list at one time, but I just noticed that it was not in the list either. So, I re-added it to the list. Then, as an experiment, I deleted the folder. Then I opened System Preferences and observed my "Do not back up" list. Yup, it was no longer listed! I re-created the folder, re-opened System Preferences. Yup, it was still not listed.
So there is no way to permanently "Do not back up" a folder if it ever disappears temporarily.
But there's an even worse scenario, although I can't reproduce this because at this time I don't have the hardware available to connect two external drives at once. I've noticed that the same deletion from "Do not back up" happens with external drives. Think about it. Let's say you connect your Time Machine backup drive, and at the same time connect an Other external drive. Tell Time Machine to "Do not back up" the Other drive. OK, it won't back it up, until you disconnect it, but then it gets deleted from the list. Then, if you ever connect this Other drive and your Time Machine drive simultaneously, and backup time rolls around, and say this Other drive has 100 GB of movies on it (a common use for external drives), Time Machine is going to copy all ****** 100 GB to your backup drive! That will likely fill it up with movies you had backed up elsewhere, and cause older archives of important files from your internal drive to be deleted. And since Time Machine doesn't give you any view of how much space is being devoted to what items, if you hadn't read this post, you probably wouldn't even know what hit you. Arghhhhh!
Maybe it's not a bug. Could it be a secret feature for selling more 1000 GB Time Capsules?
Intel Core Duo Mac Mini Early 2006, Mac OS X (10.5.2)