Ubuntu cannot find module "l2arc_rebuild_enabled"

[darkshvein]

Good day.
I tried to make l2arc cache persistent after reboot,
add option to /etc/modprobe.d/zfs.conf
options zfs zfs_arc_max=6294967296

 but after reboot:

dmesg
[ +0,011105] zfs: unknown parameter 'l2arc_rebuild_enabled' ignored

all modules?
 ls /sys/module/zfs/parameters/l2arc_
l2arc_feed_again l2arc_feed_min_ms l2arc_feed_secs l2arc_headroom l2arc_headroom_boost l2arc_noprefetch l2arc_norw l2arc_write_boost l2arc_write_max

 5.4.0-81-generic, ubuntu 20.04
zfs-linux - are correct bugreport package?

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: zfsutils-linux 0.8.3-1ubuntu12.12
ProcVersionSignature: Ubuntu 5.4.0-81.91-generic 5.4.128
Uname: Linux 5.4.0-81-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.18
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Fri Aug 20 20:39:14 2021
InstallationDate: Installed on 2019-12-28 (600 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
SourcePackage: zfs-linux
UpgradeStatus: Upgraded to focal on 2020-04-23 (483 days ago)
modified.conffile..etc.sudoers.d.zfs: [inaccessible: [Errno 13] Отказано в доступе: '/etc/sudoers.d/zfs']

[Simon Déziel (sdeziel)]

FYI, the 5.4 kernel ships with a ZFS module that predates the l2arc_rebuild_enabled parameter. You might want to switch to the HWE kernel (https://wiki.ubuntu.com/Kernel/LTSEnablementStack) that will provide this. As such, I will mark this bug as invalid.

[darkshvein (darkshvein)]

Simon, thank you for fast response,
I boot with HWE, and watch with l2arc_rebuild_enabled ,
tldr, zfs L2ARC cache persistent now after reboot. Awesome!
 It is a small foggy situation with kernels, I was sure, that using default ubuntu kernel. 🤔

It is possible to add this note in any Ubuntu zfs packages description? maybe 'zfsutils-linux'