As per the ArchZFS repository README: ‘‘occasionally the OpenZFS project gets behind on stable support for the latest Linux Kernel release. This means that if Linux 4.15 is released to core, but the latest stable release of OpenZFS does not support Linux 4.15, it is not possible to perform a system update. Sometimes it can take a few days, a few weeks, or a month to release a new stable version of OpenZFS’’. Based on the good ol’ Gentoo memories, you might think that the package manager of this ultramodern distribution surely can handle different kernel versions installed at the same time? Unfortunately, the implementation reality of pacman, the package manager of ArchLinux follows a different stereotype.

See my ArchZFS-compatible kernel packages repository that offers a solution for this problem.

Update on 2020-12-21: #

Moving and splitting the repo, a failed haproxy upgrade, and the recent package signature bug found in repo-add script triggered quite some people to open issue topics on various platforms such as archzfs ‘upstream’ github, Arch forums (wtf?) reddit (seriously wtf man, for this last two I had to register an account to react for), my private email registered for AUR account and finally on the best on-topic place, this very blog post.

So I came to a conclusion. The scripts were available in a gist (albeit outdated as of now) but time has come to create the very own github repository for the scripts that creates packages on kernels.archzfs.com. So, from now on–except for this blogpost’s comment section–I will not answer to issues posted anywhere else than the issue tracker or discussion section of the kernels.archzfs.com scripts repository.

Update on 2020-12-17: #

Due to new packages with conflicting kernel versions appearing in upstream repo this repository had to split up into many repositories each referencing different kernel packages supported by archzfs. From now on please use the kernels.archzfs.com repository as below:

[zfs-<name-of-your-kernel-package-used-here>]
Server = http://kernels.archzfs.com/$repo/

So, in case you use the linux-lts kernel package, you’d specify the ZFS kernels repo as:

[zfs-linux-lts]
Server = http://kernels.archzfs.com/$repo/

Update on 2020-09-10: #

As previously introduced I moved this repository off of my blog domain. In odder to use the repository from the new location simply change your previous pacman.conf entry to this one:

[archzfs-kernels]
Server = http://kernels.archzfs.com/$repo/$arch

Or this one if you want to be really minimalist:

[kernels.archzfs.com]
Server = http://$repo/

If you use ZFS on Arch Linux and wanted to upgrade your systems with your kernel, i bet you encountered the issue of actual official Arch Linux repository kernel versions can differ from the ArchZFS package expected kernel versions.

Please note that the post below applies to the ArchZFS ‘precompiled kernel modules’ packages. DKMS version of ArchZFS doesn’t have this issue (it has other issues)

The issue #

As stated, this discrepancy, when happens can block the whole upgrade process unless archzfs (repo for Arch Linux ZFS port) maintainers keep up with the current kernel versions or you manually instruct pacman to neglect upgrading of the kernel packages.

This issue unfolds like to following:

First you upgrade repo db files as usual:

# pacman -Sy
:: Synchronizing package databases...
 core           129.7 KiB  12.7M/s 00:00 [----------] 100%
 extra         1620.4 KiB  26.4M/s 00:00 [----------] 100%
 community        4.4 MiB  49.1M/s 00:00 [----------] 100%
 multilib       170.8 KiB  0.00B/s 00:00 [----------] 100%
 archzfs         21.7 KiB   167K/s 00:00 [----------] 100%
 archzfs.sig    310.0   B  0.00B/s 00:00 [----------] 100%

And then you start the upgrade process:

# pacman -Su
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...
error: failed to prepare transaction (could not satisfy dependencies)
:: spl-linux-lts: installing linux-lts (4.14.44-1) breaks dependency 'linux-lts=4.14.41-1'
:: zfs-linux-lts: installing linux-lts (4.14.44-1) breaks dependency 'linux-lts=4.14.41-1'

And bam, the required kernel is not in the official core repo anymore. Only a newer kernel is available, at the time of writing this post it is:

# pacman -Ss ^linux-lts$ 
core/linux-lts 4.14.44-1 [installed: 4.14.36-1]
    The Linux-lts kernel and modules

See the following timeline to be more clear on what is happening and what this repo can do for you:

Thus, this repo can come handy, when you are behind with the most recent ZFS supported kernel version but there’s a newer ArchZFS supported kernel version that you want to upgrade to.

How can we obtain the required version for ZFS?

My solution #

Add my repo to pacman configuration file and refresh the repo dbs.

# cat >> /etc/pacman.conf <<_
> [archzfs-kernels]
> Server = http://end.re/\$repo/
> _
# pacman -Sy
:: Synchronizing package databases...
 core                      129.7 KiB  12.7M/s 00:00 [----------] 100%
 extra                    1620.4 KiB  26.4M/s 00:00 [----------] 100%
 community                   4.4 MiB  88.3M/s 00:00 [----------] 100%
 multilib                  170.8 KiB  0.00B/s 00:00 [----------] 100%
 archzfs is up to date
 archzfs-kernels             2.7 KiB  0.00B/s 00:00 [----------] 100%

After that, you can start upgrading as usual:

# pacman -Su
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...
error: failed to prepare transaction (could not satisfy dependencies)
:: spl-linux-lts: installing linux-lts (4.14.44-1) breaks dependency 'linux-lts=4.14.41-1'
:: zfs-linux-lts: installing linux-lts (4.14.44-1) breaks dependency 'linux-lts=4.14.41-1'

But it still won’t work. Why? The thing is that even if the required version exists in my repo, pacman won’t try to install/use it by itself. It would boil out with the very same message on the next run of pacman -Su. The trick is that we have to hint the required dependent version of the kernel itself:

# pacman -Su linux-lts=4.14.41-1
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...

Package (50)         Old Version   New Version   Net Change   Download Size

community/apcupsd    3.14.14-2     3.14.14-3       0.04 MiB        0.24 MiB
extra/bind-tools     9.12.1.P2-1   9.13.0-1       -0.25 MiB        1.61 MiB
[...]

If you want to have headers (for using other DKMS modules like VirtualBox host modules) you can install the relevant linux header packages at the same time:

# pacman -Su linux-lts{,-headers}=4.14.41-1

See in it action #

After upgrading again #

A regular ArchLinux upgrade fails when the stable kernel package is newer than the one ArchZFS module packages are compiled against:

# pacman -Syu
:: Synchronizing package databases...
 core                      129.7 KiB  12.7M/s 00:00 [----------] 100%
 extra                    1620.4 KiB  26.4M/s 00:00 [----------] 100%
 community                   4.4 MiB  88.3M/s 00:00 [----------] 100%
 multilib                  170.8 KiB  0.00B/s 00:00 [----------] 100%
 archzfs is up to date
 archzfs-kernels is up to date
resolving dependencies...
looking for conflicting packages...
error: failed to prepare transaction (could not satisfy dependencies)
:: installing linux-lts (4.14.45-1) breaks dependency 'linux-lts=4.14.41-1' required by spl-linux-lts
:: installing linux-lts (4.14.45-1) breaks dependency 'linux-lts=4.14.41-1' required by zfs-linux-lts

If your most recent ArchZFS matching linux kernel modules and other ZFS packages are already installed, you’ve got no other options than to ignore the upgradde of the newer kernel packages until the ArchZFS repository keeps up again:

# pacman -Su --ignore=linux-lts{,-headers}
:: Starting full system upgrade...
warning: linux-lts: ignoring package upgrade (4.14.41-1 => 4.14.45-1)
warning: linux-lts-headers: ignoring package upgrade (4.14.41-1 => 4.14.45-1)
resolving dependencies...
looking for conflicting packages...

Package (50)         Old Version   New Version   Net Change   Download Size
[... upgrading of other packages proceeds as usual ...]