===[REPORT]==== [Disk BUS : IDE] .. <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <source dev='/dev/mapper/vg02-vg02--labmysql01'/> <target dev='hdb' bus='ide'/> <address type='drive' controller='0' bus='0' target='0' unit='1'/> </disk> .. ===
* While writes are going on in the KVM guest + os-prober ENABLED on the Hypervisor : $ time update-grub Generating grub configuration file ... Found linux image: /boot/vmlinuz-4.4.0-21-generic Found initrd image: /boot/initrd.img-4.4.0-21-generic done real 0m2.115s user 0m0.308s sys 0m0.228s * While writes are NOT going on in the KVM guest + os-prober ENABLED on the Hypervisor : $ time update-grub Generating grub configuration file ... Found linux image: /boot/vmlinuz-4.4.0-21-generic Found initrd image: /boot/initrd.img-4.4.0-21-generic done real 0m1.379s user 0m0.272s sys 0m0.248s === [Disk BUS : VirtIO] .. <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <source dev='/dev/mapper/vg02-vg02--labmysql01'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </disk> .. === * While writes are going on in the KVM guest + os-prober ENABLED on the Hypervisor : $ time update-grub Generating grub configuration file ... Found linux image: /boot/vmlinuz-4.4.0-21-generic Found initrd image: /boot/initrd.img-4.4.0-21-generic done real 0m12.195s user 0m0.316s sys 0m0.304s * While writes are NOT going on in the KVM guest + os-prober ENABLED on the Hypervisor : $ time update-grub Generating grub configuration file ... Found linux image: /boot/vmlinuz-4.4.0-21-generic Found initrd image: /boot/initrd.img-4.4.0-21-generic done real 0m1.295s user 0m0.308s sys 0m0.180s ===[END]==== ** Tags added: sts ** Summary changed: - update-grub slow with raw LVM + VirtIO bus + update-grub slow with raw LVM source dev + VirtIO bus ** Description changed: update-grub (grub-mkconfig) is slow to complete when there is some write disk activity on 1 or more KVM guests configure with a raw LVM2 backend + Virtio Bus type. Situation ONLY reproducible with "VirtIO", thus not reproducible with Bus type : IDE, SCSI, ... using the same exact Hypervisor and KVM guest. (Just changing the bus type at the VM level) VirtIO configuration : <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <source dev='/dev/mapper/vg02-labmysql01'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> Additional note : - * Disabling os-prober, doesn't help much, on my test I saved 1 second. * Reproducible with upstream kernel v4.10 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1666555 Title: update-grub slow with raw LVM source dev + VirtIO bus To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1666555/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
