Adding the option as an available option would be perfect and all I or most macOS users might need! Thank you!

I do want to push back a little tho on your statement that it is not block cloning. While yes, all that this configuration option does is enable server-side copy, that is a prerequisite for block cloning happening. Whatever configurations are already in place to leverage block cloning appear to apply when macOS requests a server-side copy. See my observations below:

Notice in the video how the copy is now happening server-side (bandwidth usage) but also there is no reduction is available space on the server? This does not happen when writing new data to the server - the available storage always decreases as new data is written. See ZFS dataset usage below.

Dataset usage before duplication of 29.7 GB folder

Dataset usage after duplication of folder (in finder with fruit:copyfile = yes in SMB config)

Please correct me if I’m wrong, but doesn’t the increased used/referenced without the decrease in available storage mean that block cloning was used in the copy? If so, then while fruit:copyfile = yes does not directly enable block cloning, it appears to be the only missing prerequisite to allow macOS to leverage the existing block cloning implementation.

That’s not block cloning. It’s the vfs_fruit copyfile implementation. It’s also a non-standard configuration. We could perhaps enable by default now for future releases. It’s a problem because MacOS doesn’t actually even attempt to perform server-side copies on non-MacOS servers.

We’ll probably never enable vfs_fruit by default due to other reasons, but it’s probably not a bad idea to enable when someone explicitly selects this option.

As of last time I checked MacOS still does not implement the SMB IOCTL for block cloning.

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