how large disk space for mac time machine

And this is their relevant article about full disks: (or try the wayback machine). Let's say that you have your 120Gb current system, and some months down the line you install OS X Mavericks when it's released - this may up your used space to (all figures are estimates) 130Gb, but it's not just 10Gb worth of extra files, it might be 35Gb of changed files, and 5Gb of new files, resulting in a 40Gb change for Time Machine. If that's not your case, then there's this one site resource for all things Time Machine. Most of the time I run into problems when I want to copy the Time Machine backup from an old drive to a new, larger drive. In fact, if a backup is not automated, you won't do it as often as you should thus making it most likely a useless backup for when you need it, it shall be outdated.

But that will beat most of the advantages of automated backup.

Of course, you can also keep manually deleting backed up data to make the message go away every time it appears. 2 TB disks are quite affordable nowadays, specially if you consider how much it would cost you to lose your data. You probably have a disk that's too small! And you'll be better off either reducing how much data you want to backup, by excluding some folders from it (under TM options), or simply buying a bigger disk. The problem is, for most cases, TM disk should be at least twice as big (as your data). This has become quite an issue as I now need to partition my drive but disk utility currently shows 146 gb as purgeable and only 36 gb as free. I never had this problem until I tried using my 1TB disk to backup my main drive (256gb) plus my extra drive (750gb). I recently installed the MacOS Sierra beta and have recently noticed that whenever I free up space on my mac, Disk Utility adds the freed space to the purgeable portion rather than the free portion.

How large disk space for mac time machine