Author here. A big thank you to you all for your interest in muxfs! I will try to answer all of your questions as best I can.
The concept sounds good, but you also need people to review the FUSE implementation as well as muxfs. And test, and so on. One question: do you plan to implement "concatenation" of filesystems, so you can build one very large muxfs system (10s of terabytes) ?
The OpenBSD FUSE implementation is in base so it should already be well audited.
I don't plan to add "concatenation" as you have described, however this can, in theory, be approximated by layering muxfs on top of multiple RAID0s.
Other than lack of support for NAS file systems in OpenBSD, is there a reason not to use ZFS (in favor of another file system providing similar features)?
The muxfs source code is a lot smaller than that of ZFS so if security is a concern to you then you might find muxfs easier to audit than ZFS. It also compiles quickly so could be a good match for a source-based system. This said I never aimed to "beat" ZFS.
I appreciate how clear you are about the chosen trade-offs and I am also quite impressed by the extent to which the install instructions include "and now here's how you check that worked" commands - I'm sure somebody reading this will think "well, yes, obviously you should include those" but it's not as common as I might like and your version thereof is notably thorough.
would porting ZFS have been worthwile? I know the CDDL is likely considered toxic to have in the kernel but even in a FUSE way might be worthwhile here, no?
Porting ZFS to OpenBSD has been attempted before. See this blog post from 2013: https://flak.tedunangst.com/post/ZFS-on-OpenBSD
Ahh ok. Makes sense. Seems this was to include it in the kernel though. I wonder if I fully user space solution would have been doable? (Unlikely I guess)
The muxfs source code is a lot smaller than that of ZFS so if security is a concern to you then you might find muxfs easier to audit than ZFS. It also compiles quickly so could be a good match for a source-based system. This said I never aimed to "beat" ZFS.
I appreciate how clear you are about the chosen trade-offs and I am also quite impressed by the extent to which the install instructions include "and now here's how you check that worked" commands - I'm sure somebody reading this will think "well, yes, obviously you should include those" but it's not as common as I might like and your version thereof is notably thorough.
Thanks! I'll try to remember this for any future blog entries.
Porting ZFS to OpenBSD has been attempted before. See this blog post from 2013: https://flak.tedunangst.com/post/ZFS-on-OpenBSD
Ahh ok. Makes sense. Seems this was to include it in the kernel though. I wonder if I fully user space solution would have been doable? (Unlikely I guess)
There is a FUSE implementation of ZFS for Linux but it is still in development. Porting it at this stage could be tricky.
would porting ZFS have been worthwile? I know the CDDL is likely considered toxic to have in the kernel but even in a FUSE way might be worthwhile here, no?