APFS is everything btrfs wants to be, with a wider user-base and no reputation for running out of space and then corrupting your data. You should be able to setup the Thunderbolt device with an APFS for snapshots and use Lempel-Ziv family compression like deflate, LZVN and LZFSE (says Wikipedia).
I get that’s not what you’re asking for, but I can’t imagine native macOS support for btrfs without running a VM or running Linux instead of macOS.
Maybe OP wants checksums, which are especially a good idea on removable storage when the connection may not be ideal and cause random drop-outs, or when unplugging it before the drive has committed everything to NAND.
macos isn’t particularly good for this kind of filesystem manipulation, it’s very much a “just let us handle that” situation. There is no btrfs driver or anything, you’d have to run linux for that. APFS doesn’t expose any configurables like you’re asking about for btrfs.
macos doesn’t support booting from anything other than apfs (or hfs+ for older macos) and there isn’t any way to do what you’re asking for regarding the internal/boot drives.
Really depends what you’re trying to do here but I’d say your options are:
go with apfs, this will “just work” on macos and is a copy-on-write filesystem conceptually similar to btrfs, complete with snapshots and subvolumes, but you can’t manually configure things like compression, cache, discard et al
go with btrfs, you can customise it to your heart’s content with every mount option you’re asking for, but it will need to then be shared with macos over the network;
2a) mount the btrfs filesystem in a VM, expose that filesystem to the network with nfs or smb, and mount the nfs/smb share in macos
2b) mount the btrfs filesystem on a nas or other computer, expose that filesystem to the network with nfs or smb, and mount the nfs/smb share in macos
I have to ask, why is it so important to configure your drives in this way? Why not just let the OS do its thing?
fragmentation isn’t really a concern on flash storage, you don’t need to defrag the filesystem
FWIW you can run linux distros on both of those mac minis. Asahi linux supports the m1 mini and the 2018 mini is just a bog standard intel system for the most part.
thanks for all that its very informative
an to your last question about why , its just i got used to setting an
an using said filesystem an options on an for all my linux pc over the past 10 years
an like a reflex every new build i do i just copy an paste
the custom string an go , an now that iv gone over to mac
for some select things iv been trying to find out out if
i could do the same an how. but if im hearing all you guys right
with apfs i don’t need to worry about it
thou i do want to know how to set all system snapshots to
be done to an external thunderbolt drive instead of my internal
drive with its limited 128gb if i can ?
Timemachine should do that. Not exactly sure how it works internally but I believe it makes a snapshot of the local drive then transfers to the external one.