I am running Mac OS Catalina 10.15.6 with APFS formatted disk on an unsupported MAC using dosdude1 guide. My experience from windows is I had to make careful calculations on pagefile.sys and run into limits on swap and memory. Since I’m new to Mac, I wish to avoid any mistakes and learn how to manage things properly.

This is the view of my disk

Disk View

I have 4 Gigs of RAM on my system.

I want to increase the sizeof the Virtual Memory VM (which is 3.22 GB currently).

I have searched the internet in vain. Even a question in Ask Different has not been answered. My terms to solve this on windows aren’t helping me on Mac.

How do I achieve my goals and choose which size I should allocate?

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    There is no limit on virtual memory, it gets created on demand without delay or constraint. Since there is no realistic limit imposed by the operating system, your question makes no sense. This seems like an XY problem. What actual thing are you seeking to do with your disk? – bmike Aug 23 '20 at 14:57
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    Again - why would you define or impose a limit on virtual RAM? OS X provides approximately 18 exabytes of addressable space for 64-bit processes. How is 17 exabytes not enough for you? I’m not going to vote to close your question, but this isn’t something that’s needed on iOS or macOS. They went full 64 bit 8+ years ago – bmike Aug 23 '20 at 15:01
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    If you want to improve performance, then add more RAM and fit an SSD. Don't spend your time being an Operating System. Let the OS do that. – benwiggy Aug 23 '20 at 15:30
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    I so appreciate your clarifications. Forgive my large edit. This deserves +1 and some great answers and votes. It’s never wrong to not know or be willing to learn. Welcome to Ask Different! – bmike Aug 23 '20 at 15:38
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    Thanks @bmike . You make me feel welcome – Hikmat E Ustad Aug 23 '20 at 15:42

The short answer, is you do nothing. The system decides what memory gets swapped to disk and allocates space as needed. The system allocates virtual memory addresses up to ~18 exabytes so that it can then swap as needed.

Note: Unlike most UNIX-based operating systems, OS X does not use a preallocated disk partition for the backing store. Instead, it uses all of the available space on the machine’s boot partition.

You may just have to choose programs that use macOS better if your system is in memory pressure and you can’t wait for things to work. Virtual memory and swap guarantee that programs eventually run when you over load the actual resources available. There is no need to change any tuning or limits on iOS or macOS.

Even better, containers let you share space and not get jammed with pagefile.sys blocking space. I recommend exactly what you propose, APFS containers to share all possible space. Add an inexpensive external drive and let time machine back everything up so you are free to experiment without losing any games or data.

  • I have 320Gigs of disk with single container disk 1 with 5 volumes. Lets say I want to add a volume for storing all my games. I am going to allocate 60 Gigs to Catalina (containing Mac OS + Mac OS Data)(does that 60 Gig include the 3.22 GB VM?), therefore I would be left with the remaining volumes to store and play my epic games. Now when I play epic games the VM size would expand; so am I shooting my leg allocating 60 Gigs to Catalina or should I allocate more? Also will VM be pressurized since it is within those 60 Gigs or will it pick up free space from my Game Volume. Please consider – Hikmat E Ustad Aug 23 '20 at 15:22
  • @HikmatEUstad you are free to allocate at will on APFS. All volumes share free space and the space on disk does not contain the VM system other than if swap exhausts all free space. Let’s cross that bridge if you ever reach it. I say game on - you are micromanaging storage that’s not needed – bmike Aug 23 '20 at 15:24
  • Now I’m beginning to get why you ask - astute questions and apologies if my understanding of your situation takes me time to process. – bmike Aug 23 '20 at 15:25
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    If your drive fails, it all fails. Use an external Time Machine drive for disaster recovery. macOS is not like Windows in so many ways. An APFS container beats a traditional partitioning structure hands down, as the sizes are continually flexible, not constrained like partitions. – Tetsujin Aug 23 '20 at 15:35
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    There’s hope they’ll be ready for Big Sur. I’m willing to try just about anything that supports the new OS today... steamcommunity.com/discussions/forum/2/2577697524294908642 @Tetsujin may be water under the bridge now... – bmike Aug 23 '20 at 16:36

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