TL;DR: use BTRFS or proxy the ZFS via NFS
@RJDan said in zfs on Ubuntu touch:
[...] better supported on linux, it seemed to be a clear win for zfs.
Well, unfortunately that is not the case, ZFS is not supported without adding kernel modules via DKMS. That is because of licensing issues which prevent it from being built-in the kernel like BTRFS and EXT4. DKMS cannot work on Halium kernels as they are based on patched downstream android kernel.
I thought FUSE was an option, but after trying to install it on my device I found out zfs-fuse is deprecated, and I couldn't make it work.
So the only way is to build the kernel with patches for the ZFS module, beforehand. This is however very complex and I wouldn't recommend it.
There is a workaround, to have a NFS/Samba as a proxy to the ZFS file system so that the UT device accesses the file system remotely.
The more straight-forward approach is to change the file system to BTRFS, assuming it meets your use cases. If you only need snapshots and backups, you should be fine.