I hit this today, and filed bug 1873917 before dupe'ing it to this. I'd think that the main pain points are a.) using overlay in a container that is backed by zfs via lxd b.) using overlay when using zfs root (https://didrocks.fr/2019/10/11/ubuntu-zfs-support-in-19.10-zfs-on-root/)
I attached a re-create https://launchpadlibrarian.net/475448177/test- overlay -- 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/1718761 Title: It's not possible to use OverlayFS (mount -t overlay) to stack directories on a ZFS volume Status in zfs-linux package in Ubuntu: Confirmed Bug description: ---------- Configuration # echo -e $(grep VERSION= /etc/os-release)\\nSIGNATURE=\"$(cat /proc/version_signature)\" VERSION="16.04.3 LTS (Xenial Xerus)" SIGNATURE="Ubuntu 4.10.0-35.39~16.04.1-generic 4.10.17" # dpkg --list | grep zfs ii libzfs2linux 0.6.5.6-0ubuntu18 ii zfs-doc 0.6.5.6-0ubuntu18 ii zfs-initramfs 0.6.5.6-0ubuntu18 ii zfs-zed 0.6.5.6-0ubuntu18 ii zfsutils-linux 0.6.5.6-0ubuntu18 ---------- Fault: Creating an overlay of multiple directories on a ZFS volume does not work # df /var/tmp Filesystem Type 1K-blocks Used Available Use% Mounted on tank07/var/tmp zfs 129916288 128 129916160 1% /var/tmp # mkdir /var/tmp/{lower,middle,upper,workdir,overlay} # mount -t overlay overlay -olowerdir=/var/tmp/middle:/var/tmp/lower,upperdir=/var/tmp/upper,workdir=/var/tmp/workdir /var/tmp/overlay mount: wrong fs type, bad option, bad superblock on overlay, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. # dmesg|tail -1 [276328.438284] overlayfs: filesystem on '/var/tmp/upper' not supported as upperdir ---------- Control test 1: Creating an overlay of multiple directories on another filesystem works # df /tmp Filesystem Type 1K-blocks Used Available Use% Mounted on tmpfs tmpfs 1048576 133492 915084 13% /tmp # mkdir /tmp/{lower,middle,upper,workdir,overlay} # mount -t overlay overlay -olowerdir=/tmp/middle:/tmp/lower,upperdir=/tmp/upper,workdir=/tmp/workdir /tmp/overlay # mount | grep overlay overlay on /tmp/overlay type overlay (rw,relatime,lowerdir=/tmp/middle:/tmp/lower,upperdir=/tmp/upper,workdir=/tmp/workdir) ---------- Control test 2: Creating an overlay using AuFS works on ZFS volume and elsewhere # mount -t aufs -obr=/tmp/lower:/tmp/middle:/tmp/upper:/tmp/workdir none /tmp/overlay # mount -t aufs -obr=/var/tmp/lower:/var/tmp/middle:/var/tmp/upper:/var/tmp/workdir none /var/tmp/overlay # mount | grep aufs none on /var/tmp/overlay type aufs (rw,relatime,si=9ead1ecae778b250) none on /tmp/overlay type aufs (rw,relatime,si=9ead1ec9257d1250) ---------- Remark While the use of AuFS can be used as a workaround in the above scenario, AuFS in turn will not work with [fuse.]glusterfs mounts (this has been documented elsewhere). Given that OverlayFS is part of the (upstream) kernel and Ubuntu now officially supports ZFS, the above should be fixed. --- AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Sep 18 16:12 seq crw-rw---- 1 root audio 116, 33 Sep 18 16:12 timer AplayDevices: Error: [Errno 2] No such file or directory ApportVersion: 2.20.1-0ubuntu2.10 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: DistroRelease: Ubuntu 16.04 IwConfig: Error: [Errno 2] No such file or directory Lspci: Error: [Errno 2] No such file or directory Lsusb: Error: [Errno 2] No such file or directory MachineType: Red Hat KVM NonfreeKernelModules: zfs zunicode zavl zcommon znvpair Package: linux (not installed) PciMultimedia: ProcFB: 0 cirrusdrmfb ProcKernelCmdLine: BOOT_IMAGE=/ROOT/ubuntu1604@/boot/vmlinuz-4.10.0-35-generic root=ZFS=tank07/ROOT/ubuntu1604 ro ProcVersionSignature: Ubuntu 4.10.0-35.39~16.04.1-generic 4.10.17 RelatedPackageVersions: linux-restricted-modules-4.10.0-35-generic N/A linux-backports-modules-4.10.0-35-generic N/A linux-firmware 1.157.12 RfKill: Error: [Errno 2] No such file or directory Tags: xenial Uname: Linux 4.10.0-35-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: _MarkForUpload: True dmi.bios.date: 04/01/2014 dmi.bios.vendor: SeaBIOS dmi.bios.version: 1.9.1-5.el7_3.3 dmi.chassis.type: 1 dmi.chassis.vendor: Red Hat dmi.chassis.version: RHEL 7.3.0 PC (i440FX + PIIX, 1996) dmi.modalias: dmi:bvnSeaBIOS:bvr1.9.1-5.el7_3.3:bd04/01/2014:svnRedHat:pnKVM:pvrRHEL7.3.0PC(i440FX+PIIX,1996):cvnRedHat:ct1:cvrRHEL7.3.0PC(i440FX+PIIX,1996): dmi.product.name: KVM dmi.product.version: RHEL 7.3.0 PC (i440FX + PIIX, 1996) dmi.sys.vendor: Red Hat --- AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Sep 18 16:12 seq crw-rw---- 1 root audio 116, 33 Sep 18 16:12 timer AplayDevices: Error: [Errno 2] No such file or directory ApportVersion: 2.20.1-0ubuntu2.10 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: DistroRelease: Ubuntu 16.04 IwConfig: Error: [Errno 2] No such file or directory Lspci: Error: [Errno 2] No such file or directory Lsusb: Error: [Errno 2] No such file or directory MachineType: Red Hat KVM NonfreeKernelModules: zfs zunicode zavl zcommon znvpair Package: linux (not installed) PciMultimedia: ProcFB: 0 cirrusdrmfb ProcKernelCmdLine: BOOT_IMAGE=/ROOT/ubuntu1604@/boot/vmlinuz-4.10.0-35-generic root=ZFS=tank07/ROOT/ubuntu1604 ro ProcVersionSignature: Ubuntu 4.10.0-35.39~16.04.1-generic 4.10.17 RelatedPackageVersions: linux-restricted-modules-4.10.0-35-generic N/A linux-backports-modules-4.10.0-35-generic N/A linux-firmware 1.157.12 RfKill: Error: [Errno 2] No such file or directory Tags: xenial Uname: Linux 4.10.0-35-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: _MarkForUpload: True dmi.bios.date: 04/01/2014 dmi.bios.vendor: SeaBIOS dmi.bios.version: 1.9.1-5.el7_3.3 dmi.chassis.type: 1 dmi.chassis.vendor: Red Hat dmi.chassis.version: RHEL 7.3.0 PC (i440FX + PIIX, 1996) dmi.modalias: dmi:bvnSeaBIOS:bvr1.9.1-5.el7_3.3:bd04/01/2014:svnRedHat:pnKVM:pvrRHEL7.3.0PC(i440FX+PIIX,1996):cvnRedHat:ct1:cvrRHEL7.3.0PC(i440FX+PIIX,1996): dmi.product.name: KVM dmi.product.version: RHEL 7.3.0 PC (i440FX + PIIX, 1996) dmi.sys.vendor: Red Hat To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/zfs-linux/+bug/1718761/+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
