Question about partitions on Mac

[Falcon9]

Hello,

I'm considering installing the El Captain public beta onto a secondary partition on my rMBP 2015 running 10.10.4. I have the base model with 128GB of storage (which is more then enough for my needs, as I store any large files I don't use regularly on an external 500GB hard drive that I also use as a Time Machine backup). Currently (according to the Finder) I have 62.29 GB of free space available on my computer. However when I go to create a secondary partition the largest it will let me make it is 42.79GB. Does Apple put a limit on to how large one can make a secondary partition? From what I've heard people recommend at least 30GB for running the beta software (which is what I'm planing to do, since I don't intend to use it as a primary OS) so basically I just want to make sure I'm not limiting the amount of storage available on my main partition by more then I think I am.

Thanks.

 

[Fishrrman]

"However when I go to create a secondary partition the largest it will let me make it is 42.79GB. Does Apple put a limit on to how large one can make a secondary partition?"

I'm going to -guess- that "the limit" is created by Disk Utility, based upon the amount of "used space" it "sees". Remember that a certain amount of free space is necessary in a partition that contains the OS to handle swap files, temp files, etc.

Having said that, you shouldn't have any trouble installing ElCap into a partition that is 42gb in size -- the installation itself is probably around 8-10gb.

BUT -- I would advise you to consider doing your "experimental install" to a totally separate DRIVE, rather than a partition. I just believe it's better to keep some "extra separation" between the install of an experimental copy of the OS, and the "working copy" that you depend on day-to-day.

How many posts have you already seen here, where a user has installed a pre-release copy of the OS, has had problems, and is then wondering and asking, "how do I get back to where I was before?" ...?

 

[kohlson]

Hello,

I'm considering installing the El Captain public beta onto a secondary partition on my rMBP 2015 running 10.10.4. I have the base model with 128GB of storage (which is more then enough for my needs, as I store any large files I don't use regularly on an external 500GB hard drive that I also use as a Time Machine backup). Currently (according to the Finder) I have 62.29 GB of free space available on my computer. However when I go to create a secondary partition the largest it will let me make it is 42.79GB. Does Apple put a limit on to how large one can make a secondary partition? From what I've heard people recommend at least 30GB for running the beta software (which is what I'm planing to do, since I don't intend to use it as a primary OS) so basically I just want to make sure I'm not limiting the amount of storage available on my main partition by more then I think I am.

Thanks.

There are other partitions, you just can't readily see them. There is a recovery partition and a swap partition. And Time Machine create a hidden file to do "local backups."