Hi all, I’ve run into an issue when trying to activate an LV which resides on a read-only loop device. When I run lvchange -a y <LV Path> I get the following error: Error writing device /dev/loop0p5 at 4096 length 512. bcache_invalidate: block (4, 0) still dirty Failed to write mda header to /dev/loop0p5 fd -1 Failed to update old PV extension headers in VG recursor02-01-vg. Volume group "recursor02-01-vg" not found Cannot process volume group recursor02-01-vg I’ve observed this issue when using LVM version 2.03.02 (Debian 10) to activate the LV. The volume I’m trying to mount comes from a host which has LVM version 2.02.168 which explains why headers are attempted to be updated. The lvchange commando is part of a file restore procedure. The backup solution we are using (Xen Orchestra) creates chained .vhd files but is unable to access LVM volumes which reside across multiple PV’s. As restoring a full VM is often not required a solution was found in using vhdimount and losetup to access the data and get the required files from the backups. # vhdimount 20200714T234001Z.vhd /mnt/20200714T234001Z # losetup -P -r -f /mnt/20200714T234001Z/vhdi1 # lsblk /dev/loop0 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 42G 1 loop |-loop0p1 259:0 0 243M 1 part |-loop0p2 259:1 0 1K 1 part `-loop0p5 259:2 0 41.8G 1 part Given the error I would guess the source of this issue might be caused by the following commit: https://sourceware.org/git/?p=lvm2.git;a=commit;h=070c0d31ab3847240081e7593f959b03e716923d Is there a way I can prevent the update of the extension headers when activating the LV? With kind regards, Henk _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
