NFS -- very slow reads, much slow than `cp /nfs/path/to/file.txt ~/file.txt`. I generally suspect these have to do with some pathological behavior in the app reading the file (eg: doing a 1-byte read when linearly scanning through the file). diagnose with simple `iotop`, timing the application doing the reads vs cp, and looking at some plethora or random networking tools (eg: tcptop, ...). I've also very crudely looked at `top`/`htop` output to see that an app is not CPU-bound as a first guideline.

ZFS -- slow reads due to pool-level decompression. zfs has it's own utilities, iirc it's something like `zpool iostat` to see raw disk vs filesystem IO.

RAID -- with heterogenous disks in something like RAID 6, you get minimum disk speed. This shows up when doing fio benchmarking (the first thing I do after setting up a new filesystem/mounts). It could be that better sw has ameliorated this since (last checked something like 5ish years ago).

> Honestly this is way more appealing than fighting mergerfs when you just want explicit disk placement. Doctor + prune for orphaned symlinks is exactly what you'd need to keep things sane over time.

That's the hope!

> Saw it's written in Zig, how's that been for this kind of systems tooling?

Zig has been pretty fine. It could have just as well been done in C/C++ but as a hobby thing I value (a) fast compilation (rules out building stuff in C++ without jumping through hoops like avoiding STL altogether) and (b) slightly less foot guns than C.

The source code itself is largely written with LLM's (alternating between a couple models/providers) and has a bit of cruft as a result. I've had to intervene on occasion/babysit small diffs to maintain some structural coherence; I think this pretty par for the course. But I think having inline unit tests and instant compilation helps the models a lot. The line noise from `defer file.close();` or whatever seems pretty minor.

Zig has pretty easy build/distribution since the resulting executable has a dependency on just libc. I haven't really looked into packaging yet but imagine it will be pretty straightforward.

My one gripe would be that the stdlib behavior is a bit rough around the edges. I ran into an issue where a dir was open(2)'d with `O_PATH` by default, which then makes basically all operations on it fail with `EBADF`. And the zig stdlib convention is to panic on `EBADF`. Which took a bit or reading zulip+ziggit to understand is a deliberate-ish convention.

All this to say, it's pretty reasonable and the language mostly gets out of the way, and let me make direct libc/syscalls where I want.