Is it possible to reserve exact amount of space for the indexing and virtual memory?

I have Macbook Air with 128 GB SDD (with OS X Yosemite). When I run out of memory (free space less than 1 GB) the computer slows down and even hangs up.

I suspect that this slow down is due to the impossibility of indexing to be written on the disk and due to a lack of space for the virtual memory.

Is it possible to single out a place to be used only for paging and indexing? For example, to reserve 10 GB for that purpose?

In Linux systems there is a /var folder where these kind of stuff are written. It can be put on a separate partition and this way to reserve certain amount of space only for itself. Is it possible to do something like this on a Mac in regard to indexing and virtual memory? I would sacrifice 10-15GB for it, if is needed.


1 Answer 1


As SSDs age, it takes more and more work for them to store data. This is only made worse by having less than 1GB of space available. In my experience (with a 2010 Macbook Air, with the 250GB SSD), performance GREATLY improved when I had >10% free space.

Do what you can to give your computer some breathing room! Delete some files now!

Here's a classic article on how SSDs work. Probably TMI, but... http://arstechnica.com/information-technology/2012/06/inside-the-ssd-revolution-how-solid-state-disks-really-work/

  • I am constantly deleting files. The problem is that when the computer hang up due to low memory, deleting files is very difficult. I need a solution that will prevent me from running low of space for the most important OS X system tasks. My idea is the operating system to reserve certain amount of space and to show me – the end user – only the amount of space that I can use for my files. Commented Feb 10, 2015 at 20:22

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