zfs VS linux

https://openzfsonosx.org is a great starting place for general ZFS on Mac stuff.

I am imaging the following simple situation. I am using open ZFS on macOS (OpenZFS on OS X), and I have created a zpool with a single external USB drive. What command should I run when the drive is accidentally disconnected without properly exporting the pool?

This is completely wrong. ZFS works very well via O3X [0]. I ran my home folder off of ZFS on various Mac Pros for ~11 years. ZFS works well in Linux and FreeBSD as well.

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0: https://openzfsonosx.org/

This might be able to read the drive https://openzfsonosx.org/ But I don't know if Time Machine will jive with it.

After dabbling with early stuff from the sadly scrapped Apple effort, I started my full time Mac ZFS journey in 2011 with the then Z-410, which then became ZEVO which was 10.8 only, and then staying on that (and in turn 10.8 doho) on a Mac Pro 3,1 for a solid 4 years or so. I was really sad when that effort didn't pan out and the company got acquired and then the whole deal was killed, but O3X revived the torch and I moved directly onto that. I've carried my pool forward continuously the whole way, with snapshots and everything, all data scrubbed and known good with no more data rot. It's a damn shame events (software patents) conspired to keep that from becoming a universal native fs, but it's still a wonderful thing and Lundman's amazing consistent efforts have been fantastic. The main site at https://openzfsonosx.org/ has decently active forums for something niche.

Without Apple on board or a much bigger effort ZFS on the Mac will probably always have some real limitations particularly with the GUI. For one of my desktop systems I've migrated to running my home and data folders as HFS or APFS formatted iSCSI targets, so it's still on ZFS underneath but appears native to macOS (and that also means that the effective death of towers isn't a limit on storage). But this remains an incredible project IMO.

Also for anyone who wants some limited GUI interaction capability, there is a small project called ZetaWatch [0] which will put some ZFS control into a menubar widget.

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0: https://github.com/cbreak-black/ZetaWatch/

OpenZFS is available for MacOS and it's about as rock solid as you get in a file system. As a bonus, if you someday need to migrate the dataset to a server, you'll be able to import the zfs pool pretty easily.

Check out https://openzfsonosx.org/

Site ZFS on OSX seems down for the last few days...

>such as ZFS

FWIW, ZFS has actually been available on macOS for a long time in various iterations (MacZFS, Z-410/ZEVO, and now OpenZFS [0]). I ran it for around 11 years on a number of systems with almost all of my data on it (home folder, applications, /opt for MacPorts etc) and it was a tank. Fun project and well worth checking out. I'll always regret the various factors that meant Apple didn't adopt it as their native FS.

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0: https://openzfsonosx.org/

FFS predates FreeBSD and is in some capacity supported by all 3 major BSDs. I'm fairly confident that Linux actually supports it through the ufs driver ( https://github.com/torvalds/linux/tree/master/fs/ufs ); whether the use of different names in different places makes it better or worse is an exercise for the reader.

These are a bit easier to see what's going on:

https://github.com/torvalds/linux/commit/d5cf50dafc9dd5faa1e...

https://github.com/torvalds/linux/blob/d5cf50dafc9dd5faa1e61...

Unfortunately Github doesn't have a way to render symbols for whitespace, but you can tell by selecting the spaces that the previous version had leading tabs. Linus changed it so that the tokens `default` and the number e.g. `12` are also separated by a tab. This is tricky, because the token "default" is seven characters, it will always give this added tab a width of 1 char which makes it always layout the same as if it were a space no matter if you use tab widths of 1, 2, 4, or 8.

There was also a Gentoo effort to run atop FreeBSD[0]. The challenge of course is that afaik none of the BSD kernel ABIs are considered stable. The stable interface is the BSD libc. That said, with binfmt_misc, I don't see a reason you couldn't just run (at least some) FreeBSD binaries on Linux with a thin syscall translation layer (rather something like qemu-system) and then your layer hooked via binfmt_misc. I'm not aware of anyone who has done this for FreeBSD, but prior efforts existed as alternate binfmts for SysVr4/5 ELF binaries[2]. Either way would take some elbow grease, but you *might* even be able just reuse binfmt_elf and just have a new interpreter for FreeBSD elf.

[0] https://wiki.gentoo.org/wiki/Gentoo_FreeBSD

[1] https://docs.kernel.org/admin-guide/binfmt-misc.html

[2] https://github.com/torvalds/linux/blob/master/fs/binfmt_elf....

> The original less-than check was deemed incorrect

It was only deemed incorrect because of an information leak. Not because it's a valid use-case for user space to copy smaller portions of *hwrpb into user space. https://github.com/torvalds/linux/commit/21c5977a836e399fc71...

Correct. And the combined work needs to carry the MIT license text and copyright attributions for the MIT software authors. With binary distribution it must also be overt, not hidden in some source code drop, but directly accompanying the binary.

Many people who talk about relicensing never credit the MIT developers or distribute the MIT license text. "Because it's GPL now."

I don't think that you believe that, but many developers do.

Some don't see the need for source code scans for Open Source compliance, because the license.txt says GPL, so it's GPL. Prime example is the Linux kernel. There is code under different licenses in there, but people don't even read https://github.com/torvalds/linux/blob/master/COPYING till the end ("In addition, other licenses may also apply.") and conclude it's simply GPL 2 and nothing else.

Also be aware that sublicensing is not the same as relicensing.

> Does he have something against it?

He notoriously hates GNU Emacs, yes.

https://marc.info/?m=122955159617722

https://github.com/torvalds/linux/blob/master/Documentation/...

So If we would only count code and not comments, it is only 9489 LoC Rust. Which would be about 0.03% and if we take all lines and not only LoC it would be around 0.05%

[0] https://github.com/XAMPPRocky/tokei

[1] https://github.com/torvalds/linux/commit/b401b621758e46812da...

AIUI fsync is built on futex_waitv which has been upstreamed. So this has to be more than that.

https://github.com/torvalds/linux/commit/a0eb2da92b715d0c97b...