Does tart really copy 50 gigabytes every time tart clone is run?

[sschultze]

I want to start with a fresh VM every time, so I'm calling

tart clone ghcr.io/cirruslabs/macos-ventura-base:latest ventura-base

before doing my work. (This seems to also delete any existing VM with this name first, which is good.) Surprisingly, running ventura clone only takes a small fraction of a second, even though a 50 GB subfolder is created in the ~/.tart/vms folder.

Does tart clone or macOS really copy all the 50 GB within the SSD, putting it as risk to wear out quite fast over time if I'm running the command too often? Or is there some sector-based deduplication taking place in either tart or in the operating system itself?

Thank you in advance for clarifying.

[fkorotkov]

There is no risk of wear out your SSD. All the magic is happening thanks to APFS Copy-on-Write. In the nutshell tart copy is instant because there is no physical coping is happing and as you run your cloned VM the disk is changing and only the changes are getting written to the physical SSD.

[sschultze]

This is great, thank you! :-) And also thanks for the really quick response!