partitioning a drive with data

[zoran]

Can i partition a drive that has already got data inside it, without deleting/corrupting them?

 

[zoran]

Im working on ElCapitan

 

[D.T.]

You can add/modify/shuffle partitions, umm, I'm a little hesitant to suggest anything specific since we're talking about a potentially destructive operation if not done properly.

What exactly are you starting with and what exactly are you trying to do?

 

[rhett7660]

I would off load the data first onto another drive and then partition the drive as you want.

 

[Huntn]

Drives with unused space can be partitioned, although I won’t vouch for the 100% safety of the data on it. To be safe, back up the data first.

 

[zoran]

Im coming from a situation of a malicious hdd, so i purchased a new 1TB ssd. For data security reasons, the best thing i could do is to copy the files in the ssd, as soon as possible and then decide the partitioning part.
I was thinking of making two partitions in that ssd, one for the OS and another for siles, but dont know exactly how much space to hold for HighSierra + the apps i will use.

 

[Quackers]

Is there much unused space on the 1TB drive?
If there is plenty of space you will likely be able to shrink the main partition without any damage to what's on it.
You can then create a new partition in that free space.
But, as said, all partitioning can go wrong (though it shouldn't really).
I have certainly made mistakes in the past. Just be careful.
Just another backup is never a waste

 

[zoran]

No space available for storing the backup

 

[Quackers]

No space available for storing the backup

Is your previous backup good - as far as you know?

 

[zoran]

I think so.
Btw... how much space does HSierra consume?

 

[Quackers]

I think so.
Btw... how much space does HSierra consume?

I can't remember to be honest. How much space it needs is dependant on your intended type of use.
I've had OSes installed with in 75GB or less but I don't really store anything on those.
How much unused space is in your main partition?

 

[zoran]

How much unused space is in your main partition?

Close to 80GB

 

[Quackers]

Wow, that's not too much out of 1TB ?
If that's all that's left then your El Capitan installation may not be able to breath. Not good.

 

[zoran]

If that's all that's left then your El Capitan installation may not be able to breath. Not good.

Not be able to breath? Youre saying that because its an actual problem, or are u just saying that to make a point?
I mean, is there a minimum of free space that actually should be available?

 

[Quackers]

Not be able to breath? Youre saying that because its an actual problem, or are u just saying that to make a point?
I mean, is there a minimum of free space that actually should be available?

Ideally yes.
OSes need space just to install updates, for instance.
They also slow down once free space is used up.
Don't get me wrong 80GB is quite some space but if you want to take 50GB of that away for a new OS partition then things will start to get tight.

 

[Fishrrman]

If you want to be safe, BACK UP whatever is on the drive you want to partition BEFORE attempting to partition it.

There used to be two very useful utility apps for OS X:
- iDefrag
- iPartition

Both were published by a company called Coriolis Systems that has now discontinued them, because changes in the Mac OS and the move from platter-based drives to SSDs has diminished the need for the above apps.

However, some folks may still have a need for them.
Coriolis has graciously made available all previous versions of their software.

You can freely download them from here:

Coriolis Systems

iPartition can probably do what you want.
But again, to be safe, you should back up the drive first!