The Z File System (ZFS)
The command in this page has been tested with 5.7 kernel only, not with 5.8 and later. Please let us know if you have success with newer kernel version
Background
Instead of installing the zfs-dkms package, I've tried to build the latest version 0.8.4 from Github and zfs*.ko can be built with these commands. I've not tested if zfs work or not, so please do at your own risk.
Check kernel version
$ uname -a
Linux ubuntu 5.7.0-odroid-arm64 #1 SMP PREEMPT Ubuntu 5.7.2-202006130259~focal (2020-06-12) aarch64 aarch64 aarch64 GNU/Linux
Install
$ sudo apt purge zfs-dkms libzfs2linux zfs-zed zfsutils-linux
$ sudo apt install autoconf automake libtool zlib1g-dev uuid-dev libblkid-dev libssl-dev
$ wget https://github.com/openzfs/zfs/archive/zfs-0.8.4.tar.gz
$ tar xzvf zfs-0.8.4.tar.gz
$ cd zfs-zfs-0.8.4
$ ./configure --prefix=/usr
$ make
$ sudo make install