I moved to Ubuntu 20.04 and I do not have that problem anymore. I stopped with writing directly after the login the value to the file /sys/module/zfs/parameters/zfs_arc_max.
I now only rely on "options zfs zfs_arc_max=3221225472" in /etc/modprobe.d/zfs.conf. Problem solved in 20.04 and I tried it by loading various VMs including Windows 10 and run the updates for those VMs. The L1ARC size never exceeded 3.01 GB of the 3.00 GB I allowed. I knew it would exceed for a short period the max value, but in 19.10 at the time of the bug report, it did exceed it sometimes with 1 GB or more. I use and used conky to display L1ARC values constantly; L1ARC size uncompressed; L1ARC size compressed; max allowed vale and L1ARC hit rate and I have a tweaked bar display that would allow up to 102% :) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to zfs-linux in Ubuntu. https://bugs.launchpad.net/bugs/1854480 Title: zfs_arc_max not working anymore in zfs 0.8.1 Status in zfs-linux package in Ubuntu: Incomplete Bug description: In the past I could limit the size of L1ARC by specifying "options zfs zfs_arc_max=3221225472" in /etc/modprobe.d/zfs.conf. I tried even to fill /sys/module/zfs/parameters/zfs_arc_max directly, but none of those methods limits the size of L1ARC. It worked nicely in zfs 0.7.x. Nowadays I use a nvme drive with 3400 MB/s read throughput and I see not much difference between e.g booting the system from nvme and rebooting the system from L1ARC. Having a 96-99% hit rate for the L1ARC, I like to free up some memory, thus avoiding some delay of freeing memory from L1ARC while loading a VM. ------------------------------------------------------------------------- UPDATE: The system only limits the L1ARC, if we directly after the login write the zfs_arc_max value to the file /sys/module/zfs/parameters/zfs_arc_max. ------------------------------------------------------------------------ ProblemType: Bug DistroRelease: Ubuntu 19.10 Package: zfsutils-linux 0.8.1-1ubuntu14.1 ProcVersionSignature: Ubuntu 5.3.0-23.25-generic 5.3.7 Uname: Linux 5.3.0-23-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair ApportVersion: 2.20.11-0ubuntu8.2 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Fri Nov 29 06:19:15 2019 InstallationDate: Installed on 2019-11-25 (3 days ago) InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017) SourcePackage: zfs-linux UpgradeStatus: No upgrade log present (probably fresh install) modified.conffile..etc.sudoers.d.zfs: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers.d/zfs'] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/zfs-linux/+bug/1854480/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp