Time Machine backup drive capacity questions

[hajime]

Hi, usually I use 1TB in my MacBook Pro and 1TB external drive for my TimeMachine backup. No problem.

If I buy a mini with build-in 256GB SSD and get an external SSD of 2TB as the boot drive. Do I need to get a TimeMachine backup drive of the same capacity (in this case 2TB)?

Before I sold my MacBook Pro, I used TimeMachine to back up. I used about 700GB. I plan to restore it to the external boot SSD of the Mini. Probably I will use less than 1TB in the next few months.

 

[MarkC426]

I don't know how much data you are going to have on the 2tb boot drive, but I would get a drive double the size of your disk. This will then last you a number of years.

If you have say 1tb used at the start, straight off that's used on your TM.
Don't forget you want to keep about 25% free for optimal performance.

 

[hajime]

Do you mean keep about 25% free on the boot disk (in this case the external SSD to be connected to the Mini) for optimal performance?

If I recall correctly , when I used super duper or CCC to clone the MBP internal drive, the external one has to have at least the same as the MBP internal drive. However, TimeMachine backup drive could have less capacity as the internal drive of the MBP.

 

[MarkC426]

Any drive should really not be fully utilised, for better performance.
Even more so with an AS Mac, where everything is unified, and there are a lot of disk swaps.

The TM drive can be smaller, there needs to be enough space for a full 'initial' copy, and then more.
So depending how much is initially on your disk.

You will either need to overwrite data quicker or replace with a larger disk if starting with a smaller capacity.

For example my last TM drive I think had 3 years of backups on before I replaced it (I don't like deleting stuff, usually get another disk).

 

[hajime]

Thanks. What is AS Mac?

 

[MarkC426]

Sorry, Apple Silicon.
I assumed you where looking at an M1 mini.

 

[hajime]

Thanks

 

[KindJamz]

Figured I’d just jump on this thread

I just bought the Lacie 2tb drive from apple. I did my first time machine backup. Can I store other files on the drive? What I read seems to say that time machine uses the entire disk.

The back ups are incremental so there are mult back up’s at all times? So the file size grows with each back up?

Should I just use a 500gb drive for time machine only?

 

[KindJamz]

Also a first time Mac user. So alot of this is new to me.

 

[MarkC426]

Time Machine will use the whole drive.
Ideally you want a disk 2x (or more) your system drive.

After your initial backup of your whole drive, Time Machine will add increments based on what has changed.
So the size will increase very slowly.
You can then enter Time Machine and go to say last Tuesday to restore a file you accidentally deleted or changed today.

 

[KindJamz]

So a 500gb ext drive will be perfect for a 256gb M1 air

 

[Macky-Mac]

So a 500gb ext drive will be perfect for a 256gb M1 air

perfect? note that MarkC426 suggested "..2x (or more)..."

Over time, Time Machine will ultimately fill up all of the available space on whatever size drive you use. When that happens, it'll start deleting the oldest backups to make room for the new backups. So the bigger a drive you use for TM, the longer it will take TM to fill it up. I've had 2X TM drives fill up completely several times over the years, so now I'm using a 4X sized drive.

Yes, you can store other things on the drive you're using for Time Machine. Of course doing so will reduce the amount of space available for TM......also, how are you backing up the "other things"? For myself, I think it's best to let TM have the whole drive.

 

[KindJamz]

perfect? note that MarkC426 suggested "..2x (or more)..."

Over time, Time Machine will ultimately fill up all of the available space on whatever size drive you use. When that happens, it'll start deleting the oldest backups to make room for the new backups. So the bigger a drive you use for TM, the longer it will take TM to fill it up. I've had 2X TM drives fill up completely several times over the years, so now I'm using a 4X sized drive.

Yes, you can store other things on the drive you're using for Time Machine. Of course doing so will reduce the amount of space available for TM......also, how are you backing up the "other things"? For myself, I think it's best to let TM have the whole drive.

Well I can’t imagine a time when I would have to restore to a point 4 months ago. So I guess a 500gb will be fine. As long as I have a current backup I’ll be fine. I am a very light user.

I plan on downloading all my Apple Music library to the LaCie 2tb and use it as a picture backup. That gives me about 4 back up options.

Can you restore from a TM backup on my cloud drive?

 

[MarkC426]

Of course doing so will reduce the amount of space available for TM......also, how are you backing up the "other things"? For myself, I think it's best to let TM have the whole drive.

Agreed, I have 5 different drives all backing up to my Time Machine.
And when my previous TM was full, it went into a cupboard, and I got a larger drive.
So many years of data available.....

 

[mfram]

I just bought the Lacie 2tb drive from apple. I did my first time machine backup. Can I store other files on the drive? What I read seems to say that time machine uses the entire disk.

The back ups are incremental so there are mult back up’s at all times? So the file size grows with each back up?

Should I just use a 500gb drive for time machine only?

Yes, you may use the drive to put other files on it. Over time, TM will use more of the drive for future snapshots, but you can use the other space on the drive as you wish. Keep in mind that any files you put only on the external drive are, by definition, not backed up. So if that external drive fails you have lost those files if you haven't copied them somewhere else.

 

[wilberforce]

My TM backup is 1.4TB, for an iMac that currently using about 0.6TB. It is bigger, becuase it is retaining files from years ago, which have since been deleted on the iMac. I suggest about double the size, unless you don't mind it deleting older files