Have a Fc39 server qemu/kvm virtual machine. Trying to access the filesystem from the host machine. The following commands---
:~# modprobe nbd max_part=8
:~# qemu-nbd --connect=/dev/nbd0 /var/lib/libvirt/images/Fed39.qcow2
:~# fdisk /dev/nbd0 -l Disk /dev/nbd0: 60 GiB, 64424509440 bytes, 125829120 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 131072 bytes Disklabel type: gpt Disk identifier: 3B52A5A1-29BD-436B-8145-EEF27D9EFC97
Device Start End SectorsSizeType /dev/nbd0p1 2048 4095 2048 1M BIOS boot /dev/nbd0p2 4096 2101247 2097152 1G Linux filesystem /dev/nbd0p3 2101248 125827071 123725824 59G Linux LVM
:~# mount /dev/nbd0p3 /mnt/iso mount: /mnt/iso: unknown filesystem type 'LVM2_member'. dmesg(1) may have more information after failed mount system call.
:~# vgscan Found volume group "fedora_hpz440" using metadata type lvm2 WARNING: Couldn't find device with uuid IrbzRo-h3Fw-7s0X-3x1q-NONl-TE3b-iUeftd. WARNING: VG sysvg is missing PV IrbzRo-h3Fw-7s0X-3x1q-NONl-TE3b-iUeftd (last written to /dev/sdb). Found volume group "sysvg" using metadata type lvm2
The missing PV in sysvg is a separate qcow2 file. Just need access to the first. Is there a way to access the group from the host?
Am 15.05.2025 um 15:27 schrieb Robert McBroom via users users@lists.fedoraproject.org:
Have a Fc39 server qemu/kvm virtual machine. Trying to access the filesystem from the host machine. The following commands--- :~# modprobe nbd max_part=8 :~# qemu-nbd --connect=/dev/nbd0 /var/lib/libvirt/images/Fed39.qcow2
:~# fdisk /dev/nbd0 -l Disk /dev/nbd0: 60 GiB, 64424509440 bytes, 125829120 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 131072 bytes Disklabel type: gpt Disk identifier: 3B52A5A1-29BD-436B-8145-EEF27D9EFC97
Device Start End Sectors Size Type /dev/nbd0p1 2048 4095 2048 1M BIOS boot /dev/nbd0p2 4096 2101247 2097152 1G Linux filesystem /dev/nbd0p3 2101248 125827071 123725824 59G Linux LVM :~# mount /dev/nbd0p3 /mnt/iso mount: /mnt/iso: unknown filesystem type 'LVM2_member'. dmesg(1) may have more information after failed mount system call.
:~# vgscan Found volume group "fedora_hpz440" using metadata type lvm2 WARNING: Couldn't find device with uuid IrbzRo-h3Fw-7s0X-3x1q-NONl-TE3b-iUeftd. WARNING: VG sysvg is missing PV IrbzRo-h3Fw-7s0X-3x1q-NONl-TE3b-iUeftd (last written to /dev/sdb). Found volume group "sysvg" using metadata type lvm2
The missing PV in sysvg is a separate qcow2 file. Just need access to the first. Is there a way to access the group from the host? —
With F39 / F40 there was a (unfortunately unannounced) change in the LVM device management.
You may have to add to the vgscan command a parameter vgscan —-devices /dev/nbd0p3,/dev/{your_second_disk}
See https://docs.stg.fedoraproject.org/en-US/fedora-server/administration/lvm-ma...
Same with all the other vg… commands, specifically vgchange
Alternatively, libguestfs might be able to recognize the additional volume better.
-- Peter Boy https://fedoraproject.org/wiki/User:Pboy PBoy@fedoraproject.org
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On 5/15/25 9:27 AM, Robert McBroom via users wrote:
Have a Fc39 server qemu/kvm virtual machine. Trying to access the filesystem from the host machine. The following commands---
:~# modprobe nbd max_part=8
:~# qemu-nbd --connect=/dev/nbd0 /var/lib/libvirt/images/Fed39.qcow2
:~# fdisk /dev/nbd0 -l Disk /dev/nbd0: 60 GiB, 64424509440 bytes, 125829120 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 131072 bytes Disklabel type: gpt Disk identifier: 3B52A5A1-29BD-436B-8145-EEF27D9EFC97
Device Start End SectorsSizeType /dev/nbd0p1 2048 4095 2048 1M BIOS boot /dev/nbd0p2 4096 2101247 2097152 1G Linux filesystem /dev/nbd0p3 2101248 125827071 123725824 59G Linux LVM
:~# mount /dev/nbd0p3 /mnt/iso mount: /mnt/iso: unknown filesystem type 'LVM2_member'. dmesg(1) may have more information after failed mount system call.
:~# vgscan Found volume group "fedora_hpz440" using metadata type lvm2 WARNING: Couldn't find device with uuid IrbzRo-h3Fw-7s0X-3x1q-NONl-TE3b-iUeftd. WARNING: VG sysvg is missing PV IrbzRo-h3Fw-7s0X-3x1q-NONl-TE3b-iUeftd (last written to /dev/sdb). Found volume group "sysvg" using metadata type lvm2
The missing PV in sysvg is a separate qcow2 file. Just need access to the first. Is there a way to access the group from the host?
Thanks Peter
Had a work around already. Was able to put a workstation live on the virtual machine and access the partitions freely from it to extend the volume group and the xfs filesystem. Will keep your note in mind for future use.
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Peter Boy Uni -
Robert McBroom