Create RAM disk in macOS High Sierra (10.13.3), macOS Monterey (12.6.5), macOS Sonoma (14.5)

ramdisk-howto.md

Create RAM disk in macOS High Sierra (10.13.3), macOS Monterey (12.6.5) ARM, macOS Sonoma (14.5) ARM, macOS Sequoia (15.7.1)

Update 2023-04-24

Tested on macOS Monterey (12.6.5) with Apple M1 Pro chip (ARM architecture)

Update 2024-05-04

Tested on macOS Sonoma (14.5) with Apple M1 Pro chip (ARM architecture)

Update 2025-12-03

Tested on macOS Sequoia (15.7.1) with Apple M4 chip (ARM architecture)

LIST DISKS

diskutil list

RAMDISK CREATE

hdiutil attach -nomount -nobrowse ram://120000      # 120000 * 512bytes = ~ 61.4 MB RAM disk

                                                    # 6000000 = ~ 3 GB RAM disk

newfs_hfs /dev/disk*                                # <- * is number generated by previous command

# Aware: '/tmp/ramdisk' path MUST exist first
mount -t hfs -v /dev/disk* /tmp/ramdisk             # <- * is number generated by previous command

RAMDISK DELETE

umount /tmp/ramdisk

hdiutil detach /dev/disk*                           # <- * is number generated by previous command