Hi, this is Gary with MacMost.com. Let me tell
you why it's a bad idea to partition your Backup Drive.
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So I often see Mac users get an external drive for a backup and then decide to partition it and
use part of that drive for something else. For instance, let's say you start off with a new Mac
Mini. It could be an iMac, Mac Studio, MacBook Pro, MacBook Air. Whatever. You've got a new Mac
and let's say it has a 1TB internal Drive. You do the smart thing and decide to start a backup. So
you buy an external drive. You get a 4TB external drive. They are not that expensive now a days. You
can get one for about $90. It just plugs right in. It doesn't require any external power and it is so
small you barely notice it on your desk. So then you're ready to backup. But then you realize you
only have 1TB in your internal drive and not all of that is even used. A 4TB drive seems excessive
to back everything up. Maybe you should do something else with the rest of that space.
So you decide, maybe, to partition it. Create a 2TB backup partition and a 2TB partition that
you can use for something else. For archiving old projects and such. Then you set it up so
that the backup is just backing up to that first partition and the second partition is
free for you to use for whatever you like. That sounds like a pretty good
deal except there are two main problems with it. The first one is a show stopper!
So let's say you have a file on that Other Stuff partition.
Let's call it File A. It's an important file. Let's say one day that hard drive fails on you.
Hard drives fail. They can fail for a variety of reasons. It may not be that the hard drive breaks.
Maybe you drop it. Maybe it gets crushed. Maybe it melts in a fire. Maybe you loose it or it gets
stolen. A lot of reasons that that drive can suddenly not be available to you anymore.
When that happens that file is gone. It was on that other partition. You weren't backing it up
anywhere. But then you say, well wait a minute. I'm backing up. Can't I backup external drives
as well as internal ones. I'll backup both my internal drive and anything that is on that Other
Stuff partition to the backup partition. Maybe I'll even make the backup partition bigger or
maybe I don't really need to. So I am backing up my other stuff. So now I have two copies of that
file. One in the partition where I access it and the other is a backup. This will actually help
in some situations. If you accidentally delete that file from Other Stuff then you can recover
it from the backup partition. Or if you make a change to it you can go to the backup partition
in Time Machine and recover an older version of it. So it will help in some situations.
But you know what situation it doesn't help with is if again you loose access to that
drive for whatever reason. Now you've lost both your backup and all the things in Other
Stuff even though you actually had two copies of that file, an original and a backup. Both
of those are now gone because you don't have that drive available anymore. The short term
for this is basically Single Point of Failure. Your original and your backup are on one drive.
That drive acts as a Single Point of Failure if you loose the drive, if it gets stolen,
it melts, if a meteor hits it, whatever, you have lost the original and the backup in one
single failure. For this reason alone you should never partition a backup drive. Just have it as
your backup. Don't have any other files stored on it anywhere in another partition or otherwise.
Now here's another reason this is a bad idea. You may think that because you just have 1TB
of internal storage and maybe half of that is being used that 2TB is more than enough
space to back things up. Indeed, it will work fine for a little while. But eventually all of
the space in your backup will fill up. Now how is it possible, say if you have ½ a TB of data
that it could fill up a 2TB drive. Remember, Time Machine is an incremental backup. So it is going
to keep versions of your files as you change things. Like, for instance, as you write your
novel and your word processing document changes everyday it's going to save new versions of that
to the backup. So you can go back in time to yesterday's copy or last month's copy or the
original copy from last year. In addition, if you delete files it is still going to save a copy in
the backup. So you create a large file, maybe a video project, and now you delete it. The last
copy of that file is still going to be saved in your backup. That's the whole point of a backup.
Because if it was an accidental deletion then you want to be able to recover it and you may not
realize that you accidentally deleted it until a few days, a month, six months later. So the backup
drive will slowly fill up as you create files, modify files, and delete files. So even if you're
not using anywhere near 2TB of storage right now you eventually will hit the limit on the drive.
Now ideally it would take years to do that. But it is going to happen a lot sooner if you
decide to partition the drive and only have a 2TB backup rather than having a 4TB backup.
So you want to give Time Machine as much space as you can. Don't do something that's going to
limit the amount of space it has to backup your files. If you really need an external storage a
better situation is to just get another drive. This eliminates both problems. So
you have your 4TB Time Machine drive. It costs about $90 now. Maybe get another drive. A 2TB
or a 4TB drive. The 2TB drives are now about $60. Or just dedicate that 4TB drive to your
backup and hopefully your internal drive is enough for all your file storage. If not,
you could always use Cloud storage like iCloud Drive or any other cloud service to expand that.
So I hope this makes it clear why you should avoid partitioning your Time Machine backup drive. Give
Time Machine as much space as you can and avoid a Single Point of Failure. Thanks for watching.