zfsbootmenu

Best option to date: https://github.com/zbm-dev/zfsbootmenu A shame most distro's installers don't support it natively, but an encrypted rootfs on ZFS is great once you get it setup.

As an aside I can heartedly recommend zfsbootmenu for anyone using zfs on linux: https://github.com/zbm-dev/zfsbootmenu

We use a couple nice home-grown functions in ZFSBootMenu to help debug things. We have a zdebug logging function that's peppered liberally throughout the code base - https://github.com/zbm-dev/zfsbootmenu/blob/master/zfsbootme... Hitting ctrl-t on our main menu will, when booting with debug logging enabled, show a screen like this: https://i.imgur.com/Ge75zkP.png We also have a flamegraph profiling mechanism that can be enabled with https://github.com/zbm-dev/zfsbootmenu/blob/master/zfsbootme... . That will dump data to a serial port, which when re-assembled, can be used to produce a graph like https://raw.githubusercontent.com/zbm-dev/zfsbootmenu/master... Bash is suprisingly flexible.

A lot of what's in the Pure Bash Bible is horrifically slow. Many of those things are substantially faster, even when paying the cost of starting a new process, when you use an external and commonly available tool. I wrote a bash performance profiler that outputs data in a format that flamegraph.pl recognizes - it really helped identify where we could improve the performance of ZFSBootMenu. https://github.com/zbm-dev/zfsbootmenu/releases/tag/v1.12.0 Don't fall in the trap of thinking things have to be written entirely in bash; it's okay to use other tools to help fill in the gaps.

Does Arch Linux have boot environments (or equivalent)? Boot Environments allows the system to be upgraded, while preserving the old system environment in a separate ZFS dataset. * https://man.freebsd.org/cgi/man.cgi?beadm The beadm command is the user interface for managing ZFS Boot Environments (BEs). This utility is intended to be used by system administrators who want to manage multiple Oracle Solaris instances on a single system. * https://docs.oracle.com/cd/E86824_01/html/E54764/beadm-1m.ht... > A ZFS boot environment is a bootable clone of the datasets needed to boot the operating system. Creating a BE before performing an upgrade provides a low-cost safeguard: if there is a problem with the update, the system can be rebooted back to the point in time before the upgrade. * https://klarasystems.com/articles/m

I'm continuing to work on https://github.com/zbm-dev/zfsbootmenu . Support for Debian's initramfs-tools, more install guides for distributions, better documentation.

The problem is, ZFS support on GRUB2 hasn't been great, partly due to CDDL/GPL licensing incompatibility requiring lots of ZFS internals to be re-implemented in GRUB. This resulted in issues such as grub-probe unable to detect ZFS pools due to unsupported ZFS features[1] (including native ZFS encryption, which is a deal-breaker for many) ZBM took another approach. It provides a small initramfs image that are built on the host machine via standard method such as dracut or mkinitcpio. This image provides an interface for decrypting/mounting ZFS filesystems using the very same ZFS kernel module and tools installed on the host. After the filesystem is mounted, it then kexec'd into the host kernel. This also means ZBM doesn't completely replaced GRUB2 or syslinux. Instead, it rely on those intermediate bootloader (including EFI bootloader such

Creating and shipping a UKI means that people can just write it to a USB drive that has a vfat partition marked as an ESP. As long as the filename is BOOTX64.EFI, modern x86_64 hardware will automatically find and boot that if no other working EFI entries can be found. Since the kernel commandline is embedded in the UKI, there's no manual/error prone setup to be able to boot the file with any required/extra arguments. https://github.com/zbm-dev/zfsbootmenu/wiki/Portable-ZFSBoot...

I'm a huge fan of UKI - it's part of the underlying 'magic' of ZFSBootMenu (https://github.com/zbm-dev/zfsbootmenu/). We ship a single EFI file that is a full Linux kernel, a semi-custom initramfs and an embedded command line. With that, we can fully support root-on-ZFS because we don't have to re-implement a complex filesystem in a bootloader ... like GRUB. Because we're not trying to re-implement ZFS (or any other modern/complex filesystem), we can ALWAYS be current. If a new version of ZFS is released, all we have to do is build a new EFI executable with that baked in to the embedded initramfs. There are serious concerns with SecureBoot and being able to unlock your own bootloader - but UEFI itself is a nice universal base to target in 2022.

fzf is a fantastic tool. The main interface of ZFSBootMenu is created with it. It has a pretty solid set of scripting capabilities! https://github.com/zbm-dev/zfsbootmenu/blob/master/media/v1.... https://github.com/zbm-dev/zfsbootmenu/blob/master/zfsbootme...

This is implemented for Arch Linux with bieaz or zbm; and Ubuntu with zsys. bieaz: https://openzfs.github.io/openzfs-docs/Getting%20Started/Arc... zbm: https://github.com/zbm-dev/zfsbootmenu zsys: https://github.com/ubuntu/zsys

GRUB2 works fine with /boot on ZFS, however GRUB cannot detect ZFS dataset with native ZFS encryption (see bug[1]). The best KB right now is probably OpenZFS documentation[2] and Arch Wiki[3]. I've been using ZBM since its inclusion in void-packages. It already does everything I wanted it to, but I don't think its usage is widespread outside Void Linux community just yet. Being dependent on Dracut might be one of the reason why (I believe Arch is still using mkinitcpio). There's installation instruction for Void and Debian Buster on ZBM GitHub[4]. I used to have a separate ZBM root for void-musl and void-glibc which worked quite well (though I'm now running only void-glibc due to Nvidia). [1]: https://savannah.gnu.org/bugs/?func=detailitem&item_id=58270 [2]: https://openzfs.github.io/openzfs-docs/Getting%20Started/ind... [3]: https://wiki

Take a look at https://github.com/zbm-dev/zfsbootmenu/ . Full boot environment support for Linux, along with the ability to create a new environment from a snapshot in your bootloader, live-diff snapshots to see _when_ something changed, and even chroot into a boot environment to fix things.