Hi everyone, I'm a long time ZFS user (both on Linux and on Mac) but this is my first post - I've never stumbled upon any big issue, until now.
I have this problem with a macbook pro with Mojave 10.14.6, OpenZFS installed with brew (OpenZFS on OS X 1.9.4 Mojave.pkg).
By "disappears" here I don't mean "it's not imported", I mean actually, really disappears (no output at all from zpool import). The problem, on that particular machine at least (a macbook pro 13 unibody), and on that specific partition, is reproducible.
I create, I reboot, nothing is there anymore. diskutil list shows the pre-existing partition type, as if my zpool create command never happened (HFS+, for example).
It happens on a SSD partition (disk0s3). Other partitions are: disk0s1 -> EFI, disk0s2 -> APFS with the OS. There's also another internal disk (disk1, an HDD entirely devoted to ZFS), moreoever I use also a bunch of usb disks with ZFS. All other disks and pools work normally, without any issue.
For that partition only, whenever I reboot, disk0s3 reverts back to whatever was there before creating a ZFS pool in its place, be it a fat32 file system or a HFS one or whatever.
I've tried to search here and on the internet, but I found nothing and I got no idea about what's going on. My search results are obscured by people that cannot find their pool because it's not automatically imported, but this is not my case at all. This is not the only macOS machine on which I use ZFS - on a similar system I have exactly the same configuration, with a pool on a SSD partition and a pool on a whole disk.
Disclaimer: I posted this already on OpenZFS's github issues (probably not the best place for my problem in retrospective, I apologise for that, it occured to me only now that this forum would be better), and on StackExchange/Superuser, but no answer yet. I will report any info where I have already posted if it comes up (and close issues too, hopefully).
If anyone has any ideas about how to proceed, I would be grateful. Thanks in advance!
ggrocca