Hello smart people. Looking here, and online with a Time Machine question. It probably has a simple answer. Why does the data saved on Time Machine not match the amount on the MainDrive (attachment)? Mid 2010 MacMini El Capitan. Big & fat thanks.
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(Another) Time Machine Question
- Thread starter FlipPhoneAndy
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It's because TimeMachine stores a full backup and then incremental backups together. This allows you to go back in time (reason it is called TimeMachine) to restore a file from several different days. So for example you change a file every day for a week and then you could go back and restore it as it was on any of those days. So it is storing all of those changes each day. When the space gets low it will start removing files from the oldest backups.
Your TM backup will, after a few days, always be larger than the disk(s) being backed up. It’s because TM never throws anything away unless it absolutely has to. The initial backup will be roughly the same size of the things being backed up. After that it periodically compares that initial backup with the state of the drive(s) at that moment. Changes and new data are then added to TM but nothing is deleted unless and until the backup disk fills up. Once that happens TM will delete old data (that’s not critical to the OS) to make room for new data. In a perfect world your TM backup disk will be larger than the disk(s) being backed up.
WOW. Thanks. That makes a lot of sense. If I should ever buy a new mac, and use Time Machine to load up the new unit, I imagine, it would cleverly dispense only the latest backup -- not everything. I don't think I can afford more than a 500GB. Putting my 2010 MacMini on a diet, presently. Thanks again.
The Time Machine backup starts smaller than your hard drive because of the excluded files:
On OS X, what files are excluded by rule from a Time Machine backup?
In addition to whatever files I may choose to exclude, what files does the system exclude by rule or classification? It might make sense not to backup Trash or Caches, but I'm looking for a way to...
Not only that, but when you buy your new Mac and use Migration Assistant at first boot, you can pick the point in time to restore - it doesn't even have to be the latest backup.
Thanks. everybody. I won't even ask why Time Machine changes color. Most of the time it's orange, sometimes it's blue.