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I still can't reconcile zfs in the installer. There's no warnings or information upfront about how you will make your filesystem into a nice brick if you upgrad

I still can't reconcile zfs in the installer. There's no warnings or information upfront about how you will make your filesystem into a nice brick if you upgrade your linux kernel and forget that your filesystem has to be manually upgraded with that kernel version. Distros should not include filesystems that aren't in the kernel in their official installer. Fedora made the right decisions with btrfs. If users want zfs they don't need the official installer for it.

TheAdamAndChe 6y ago
I disagree. Part of what I love about the Linux culture is that it gives me the freedom to tinker. The Ubuntu installer makes it absolutely clear that ZFS is still experimental, but it still lets me play with it. Granted, I swiftly broke my OS and moved away from ZFS when I tried it, but I like that it let me do that.
andag 6y ago
1. You won't get a kernel update that doesn't contain zfs support, as the distro contains this. 2. Even if you install a manual kernel from outside of ubuntu you wont' brick it.. you'd just have to boot the old kernel. btrfs and zfs are.. not comparable.
- devwastaken 6y ago
  It does and did, tested on 20.10. Similar stories: https://reddit.com/r/zfs/comments/hasfax/how_do_you_update_linux_headers_without_breaking/ https://reddit.com/r/zfs/comments/hasfax/how_do_you_update_l... It's supposedly meant to "just work" but out of the box it did not. Which is a very common story with ubuntu sadly.
  - kasabali 6y ago
    That link is about Debian. Debian doesn't ship zfs module and it needs to be compiled separately for each kernel version. Ubuntu ships ZFS module in kernel package and it works without having to be compiled nor it needs header package.
scaladev 6y ago
What? They ship prebuilt zfs modules along with the kernel. # dpkg -L "linux-modules-$(uname -r)" | grep zfs.ko /lib/modules/5.4.0-70-generic/kernel/zfs/zfs.ko
taneliv 6y ago
In case of Ubuntu 21.04 it seems that DKMS magic takes care of rebuilding ZFS support whenever I install a new kernel package (yes, even one that I've built myself from mainline git---currently running 5.12-rc7). Yes, it can require manual work, if zfs-dkms does not have support for the kernel one is running. This failure should be quite visible: installation of the kernel package will end in an error. But more importantly, missing ZFS support should not brick the filesystem. The new kernel just can't mount it, which can be overcome by rebooting to an older kernel. And then addressing whatever the issue is.
- trissylegs 6y ago
  Also pretty sure Ubuntu keeps a few old versions of Linux. And GRUB uses it's own ZFS module.
stevencorona 6y ago
As much as I love ZFS, I also recently hit this issue and it was an exercise in frustration to get a running system again.
lscotte 6y ago
This is just anti ZFS FUD and completely incorrect. Ubuntu has been shipping binary modules for ZFS for several years now. I've been running servers and laptops for a couple of years with ZFS root (laptop with native ZFS encryption). The only issue I've had is Canonical breaking GRUB hooks for encrypted ZFS root - solved via systemd-boot and EFI for me. If you use DKMS, then you might have issues, but there's no need with Ubuntu (and other distros like Manjaro) anyway. Btrfs is probably never the right decision - use the FS that's right for you and your workload.
- scaladev 6y ago
  >Btrfs is probably never the right decision And you're posting anti-btrfs FUD. https://lwn.net/Articles/824855/ https://lwn.net/Articles/824855/ https://facebookmicrosites.github.io/btrfs/docs/btrfs-facebook.html https://facebookmicrosites.github.io/btrfs/docs/btrfs-facebo... Even if it's the only deployment in the world, it's more than "never". They provide strong technical reasons for using it.

TheAdamAndChe 6y ago

I disagree. Part of what I love about the Linux culture is that it gives me the freedom to tinker. The Ubuntu installer makes it absolutely clear that ZFS is still experimental, but it still lets me play with it. Granted, I swiftly broke my OS and moved away from ZFS when I tried it, but I like that it let me do that.

andag 6y ago

1. You won't get a kernel update that doesn't contain zfs support, as the distro contains this. 2. Even if you install a manual kernel from outside of ubuntu you wont' brick it.. you'd just have to boot the old kernel. btrfs and zfs are.. not comparable.

devwastaken 6y ago
It does and did, tested on 20.10. Similar stories: https://reddit.com/r/zfs/comments/hasfax/how_do_you_update_linux_headers_without_breaking/ https://reddit.com/r/zfs/comments/hasfax/how_do_you_update_l... It's supposedly meant to "just work" but out of the box it did not. Which is a very common story with ubuntu sadly.
- kasabali 6y ago
  That link is about Debian. Debian doesn't ship zfs module and it needs to be compiled separately for each kernel version. Ubuntu ships ZFS module in kernel package and it works without having to be compiled nor it needs header package.

scaladev 6y ago

What? They ship prebuilt zfs modules along with the kernel. # dpkg -L "linux-modules-$(uname -r)" | grep zfs.ko /lib/modules/5.4.0-70-generic/kernel/zfs/zfs.ko

taneliv 6y ago

In case of Ubuntu 21.04 it seems that DKMS magic takes care of rebuilding ZFS support whenever I install a new kernel package (yes, even one that I've built myself from mainline git---currently running 5.12-rc7). Yes, it can require manual work, if zfs-dkms does not have support for the kernel one is running. This failure should be quite visible: installation of the kernel package will end in an error. But more importantly, missing ZFS support should not brick the filesystem. The new kernel just can't mount it, which can be overcome by rebooting to an older kernel. And then addressing whatever the issue is.

trissylegs 6y ago
Also pretty sure Ubuntu keeps a few old versions of Linux. And GRUB uses it's own ZFS module.

stevencorona 6y ago

As much as I love ZFS, I also recently hit this issue and it was an exercise in frustration to get a running system again.

lscotte 6y ago

This is just anti ZFS FUD and completely incorrect. Ubuntu has been shipping binary modules for ZFS for several years now. I've been running servers and laptops for a couple of years with ZFS root (laptop with native ZFS encryption). The only issue I've had is Canonical breaking GRUB hooks for encrypted ZFS root - solved via systemd-boot and EFI for me. If you use DKMS, then you might have issues, but there's no need with Ubuntu (and other distros like Manjaro) anyway. Btrfs is probably never the right decision - use the FS that's right for you and your workload.

scaladev 6y ago
>Btrfs is probably never the right decision And you're posting anti-btrfs FUD. https://lwn.net/Articles/824855/ https://lwn.net/Articles/824855/ https://facebookmicrosites.github.io/btrfs/docs/btrfs-facebook.html https://facebookmicrosites.github.io/btrfs/docs/btrfs-facebo... Even if it's the only deployment in the world, it's more than "never". They provide strong technical reasons for using it.