Time Machine

It's only an incremental backup every hour. So only the things that changed will be backed up after the first full backup.

The size of each hourly backup will depend on how many things changed since the last backup. If nothing changed then nothing will be backed up other than a few kb of system data. If allot of stuff changed the backup will be bigger.

Avoid making backups of large files that change often like VMWare Fusion virtual machines. You can exclude any folders you don't want to include in the backup.

Hourly is perfect for most people.

 

Yes, every backup after the initial backup is an incremental. The daily backup is just the first hourly backup of the day.

 

Only the data that actually changed is copied to the TM disk. They use some "magic" involving links (aka "aliases") to make it look like a full backup, but only the changed files are copied.

THere really is not point in doing daily or weekly backups when you already are doing them hourly..

If you want better backups them use some other system in ADDITION to TM. Like for example rotaing a pair of backup disk to an off site location.

 

Thanks for the valuable info. I'm just wondering if snapshots taken for the system requires the external backup drive plugged in all the time, after the initial backup.

Because when I checked my time machine I found out that snapshots stopped since the last time I did a back up to the external drive!!!

thanks for the comments

 

Time Machine doesn't require the backup hard drive to be plugged in all the time and it will make a backup automatically once you connect the hard drive to the computer again.

However, if you don't have the hdd connected to the computer it is pretty much useless having time machine in the first place because the point is to have the hourly backups incase you need them.