zfs with encryption: sluggish resume from suspend, intermittent freezes

[Mike Pontillo]

I had been using Jammy on a Thinkpad T470 for months without problems.

I decided to try a fresh Ubuntu Desktop install using ZFS, using the install-time option for full-disk encryption.

After using the fresh install for a little while, I noticed that the system was "more sluggish" in the ZFS configuration (which was disappointing, but tolerable).

The "sluggishness" is especially noticeable when resuming from suspend. Typically, I'll look at the system clock and notice that it does not change for ~tens of seconds. On some occasions, it will freeze completely (even after waiting many minutes) and require a reboot.

Given that this the only difference between a "perfectly working system" and "problematic system" was the filesystem change, I strongly suspect ZFS as the cause (and/or perhaps enabling the full-disk encryption option for it during the install).

Any advice on how to further triage this and narrow down the issue would be appreciated.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: linux-image-5.19.0-46-generic 5.19.0-46.47~22.04.1
ProcVersionSignature: Ubuntu 5.19.0-46.47~22.04.1-generic 5.19.17
Uname: Linux 5.19.0-46-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Wed Jul 19 10:03:03 2023
InstallationDate: Installed on 2023-03-22 (119 days ago)
InstallationMedia: Ubuntu 22.04.2 LTS "Jammy Jellyfish" - Release amd64 (20230223)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-signed-hwe-5.19
UpgradeStatus: No upgrade log present (probably fresh install)

[Daniel van Vugt (vanvugt)]

Thanks for the bug report. When the problem is happening, please open a terminal and run:

  journalctl -b0 > journal.txt
  lspci -k > lspci.txt
  dconf dump /org/gnome/shell/ > shellsettings.txt

and attach the resulting text files here. If you couldn't run those while the problem is happening then reboot and use this instead:

  journalctl -b-1 > prevboot.txt
  lspci -k > lspci.txt
  dconf dump /org/gnome/shell/ > shellsettings.txt

[Mike Pontillo (mpontillo)]

Attached some post-reboot logs; thanks for taking a look.

[Mike Pontillo (mpontillo)]

FWIW, I switched back to ext4 and am no longer experiencing the same issues.