Debian 8 - kernel update seems to have broken ZFS

[andrewc8]

I just updated our Debian 8 machine with latest package updates ( including a kernel update) and ZFS file systems seem to have gone MIA.

What should my approach be to recover from this?

[stevepusser]

If you're using zfs-dkms, try

Code: Select all

dpkg-reconfigure zfs-dkms

as sysadmin to force a rebuild of the driver. Watch the output for any fatal errors or success message.

[andrewc8]

This was actually a very interesting problem
- the ZFS filesystem was mounted on /home
- during the package update process it seems the ZFS file system was unmounted ( thus un-mounting everything under /home)
- I logged in via SSH during the package update process - apparently right at the 'wrong time'.
- this created an empty /home/<myusername>
- on reboot ZFS would not mount as /home was not empty

Simply removing the directory under /home allowed ZFS filesystem to mount.

[andrewc8]

My last post was actually wrong. It appears the kernel update did blow away ZFS. I had reverted to the previous kernel during the boot sequence before making my analysis of what happened.

with the latest kernel...

dpkg-reconfigure zfs-dkms
failed with an error

/var/lib/dkms/zfs/0.6.5.7/build/module/zfs/zpl_inode.c: In function ‘zpl_setattr’:
/var/lib/dkms/zfs/0.6.5.7/build/module/zfs/zpl_inode.c:323:2: error: implicit declaration of function ‘inode_change_ok’ [-Werror=implicit-function-declaration]

[andrewc8]

Looks like this issue was fixed but how do I get the latest ?
https://github.com/zfsonlinux/zfs/issues/5454

[stevepusser]

The version in jessie-backports-sloppy should include the fix. Be aware that this will not upgrade smoothly to the older ZFS in Stretch if that matters to you, though stretch-backports has a yet newer version.

https://packages.debian.org/search?keyw ... ection=all

[andrewc8]

Thanks for the help!

I hope the package maintainers fix this issue.
The machine in question is a "as-shipped from DELL" 56-core/1TB RAM server class machine. I am fairly ignorant on how compatibility is maintained with updates but running a standard package update should not break the machine.

I worked around the issue by changing GRUB options so that it will always boot into the previous kernel.

[reinob]

I am fairly ignorant on how compatibility is maintained with updates but running a standard package update should not break the machine.

How did you install ZFS? the zfs-dkms package is not available for jessie. So AFAIK no "standard package update" as claimed.
From your message above you have version 0.6.5.7, which does not seem to be available for debian (at least since 2016 or so..)

[GarryRicketson]

How did you install ZFS? the zfs-dkms package is not available for jessie.

Good question, and point.

---snip---machine. I am fairly ignorant on how compatibility is maintained with updates but running a standard package update should not break the machine.

If it is a "standard package", and I mean a package from the Debian Repositories and the correct repo for the version of Debian you are using,then
no , it should not break your system.
Maybe read: https://wiki.debian.org/DontBreakDebian

Don't suffer from Shiny New Stuff Syndrome

The reason that Debian Stable is so reliable is because software is extensively tested and bug-fixed before being included. This means that the most recent version of software is often not available in the Stable repositories. But it doesn't mean that the software is too old to be useful!

Before attempting to install the newest version of some software from somewhere other than the Debian Stable repositories, here are some things to keep in mind: ---snip---

One needs to read all of it.
As for this :

I am fairly ignorant on how compatibility is maintained with updates

Then do some searches, become familiar with it.
how compatibility is maintained with updates for Debian packages
This is something you should have done, before trying to update anything.
first hit, of many : https://www.debian.org/doc/manuals/debi ... 02.en.html

[stevepusser]

6.5.9 is in jessie-backports. Perhaps 6.5.7 was in backports earlier, but I'm too lazy to search through its history at snapshot.debian.org.

Garry, the OP says it was a normal security upgrade to the standard Jessie 3.16 kernel that caused the breakage.