Why is the second disk missing? If you accidentally added it and ended up with a striped pool, as long as both disks are connected, you can import the pool normally. Then use the new device_removal feature to remove the new disk from the pool.
If you've done something crazy like pulled the disk and wiped it, then yeah, you're going to need to figure out how to import the pool read- only. I don't have any advice on that piece. -- 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/1906542 Title: echo 1 >> /sys/module/zfs/parameters/zfs_max_missing_tvds says premission error, unable to reapair lost zfs pool data Status in zfs-linux package in Ubuntu: New Bug description: root@jonipekka-desktop:~# echo 1 >> /sys/module/zfs/parameters/zfs_max_missing_tvds -bash: /sys/module/zfs/parameters/zfs_max_missing_tvds: Permission denied root@jonipekka-desktop:~# https://www.delphix.com/blog/openzfs-pool-import-recovery Import with missing top level vdevs The changes to the pool configuration logic have enabled another great improvement: the ability to import a pool with missing or faulted top- level vdevs. Since some data will almost certainly be missing, a pool with missing top-level vdevs can only be imported read-only, and the failmode is set to “continue” (failmode=continue means that when encountering errors the pool will continue running, as opposed to being suspended or panicking). To enable this feature, we’ve added a new global variable: zfs_max_missing_tvds, which defines how many missing top level vdevs we can tolerate before marking a pool as unopenable. It is set to 0 by default, and should be changed to other values only temporarily, while performing an extreme pool recovery. Here as an example we create a pool with two vdevs and write some data to a first dataset; we then add a third vdev and write some data to a second dataset. Finally we physically remove the new vdev (simulating, for instance, a device failure) and try to import the pool using the new feature. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: zfsutils-linux 0.7.5-1ubuntu16.10 ProcVersionSignature: Ubuntu 4.15.0-126.129-generic 4.15.18 Uname: Linux 4.15.0-126-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair ApportVersion: 2.20.9-0ubuntu7.20 Architecture: amd64 Date: Wed Dec 2 18:39:58 2020 InstallationDate: Installed on 2020-12-02 (0 days ago) InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725) SourcePackage: zfs-linux UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/zfs-linux/+bug/1906542/+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
