On Wed, Dec 02, 2015 at 08:53:39PM +0100, Axel Glienke wrote:> Creating snapshot: > > [root at lvmtest ~]# lvcreate -L5G -s -n root_snap /dev/centos/root > Reducing COW size 5,00 GiB down to maximum usable size 2,94 GiB. > Logical volume "root_snap" created. > [root at lvmtest ~]# lvs > LV VG Attr LSize Pool Origin Data% Meta% Move > Log Cpy%Sync Convert > root centos owi-aos--- 2,93g > root_snap centos swi-a-s--- 2,94g root 0,00 > swap centos -wi-ao---- 1,00g > > --- reboot --- > > dracut shell (missing /dev/centos/root) > > cat proc/cmdline: > BOOT_IMAGE=/vmlinuz-3.10.0-229.20.1.el7.x86_64 > root=/dev/mapper/centos_root ro rd.lvm.lv=centos/root > rd.lvm.lv=centos/swap crashkernel=auto rhgb quiet LANG=de_DE.UTF-8 > systemd.debugshouldn't you have a new grub entry with: root=/dev/mapper/root_snap rd.lvm.lv=centos/root_snap Tru -- Tru Huynh http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xBEFA581B -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: not available URL: <http://lists.centos.org/pipermail/centos/attachments/20151202/844808f0/attachment-0001.sig>
in journalctl i found: modprobe: FATAL: Module dm-snapshot not found ... Can't process LV root_snap: snapshot target support missing from kernel Zitat von Tru Huynh <tru at centos.org>:> On Wed, Dec 02, 2015 at 08:53:39PM +0100, Axel Glienke wrote: >> Creating snapshot: >> >> [root at lvmtest ~]# lvcreate -L5G -s -n root_snap /dev/centos/root >> Reducing COW size 5,00 GiB down to maximum usable size 2,94 GiB. >> Logical volume "root_snap" created. >> [root at lvmtest ~]# lvs >> LV VG Attr LSize Pool Origin Data% Meta% Move >> Log Cpy%Sync Convert >> root centos owi-aos--- 2,93g >> root_snap centos swi-a-s--- 2,94g root 0,00 >> swap centos -wi-ao---- 1,00g >> >> --- reboot --- >> >> dracut shell (missing /dev/centos/root) >> >> cat proc/cmdline: >> BOOT_IMAGE=/vmlinuz-3.10.0-229.20.1.el7.x86_64 >> root=/dev/mapper/centos_root ro rd.lvm.lv=centos/root >> rd.lvm.lv=centos/swap crashkernel=auto rhgb quiet LANG=de_DE.UTF-8 >> systemd.debug > > shouldn't you have a new grub entry with: > root=/dev/mapper/root_snap rd.lvm.lv=centos/root_snap > > Tru > > -- > Tru Huynh > http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xBEFA581BGr??e Axel
Ok, kernel needs the module dm-snapshot for snapshot support, but the modules is storage on a snapshoted-lv ... you can't make a root_snapshot with centos? Zitat von Axel Glienke <axel at glienke.cc>:> in journalctl i found: > modprobe: FATAL: Module dm-snapshot not found > ... > Can't process LV root_snap: snapshot target support missing from kernel > > > Zitat von Tru Huynh <tru at centos.org>: > >> On Wed, Dec 02, 2015 at 08:53:39PM +0100, Axel Glienke wrote: >>> Creating snapshot: >>> >>> [root at lvmtest ~]# lvcreate -L5G -s -n root_snap /dev/centos/root >>> Reducing COW size 5,00 GiB down to maximum usable size 2,94 GiB. >>> Logical volume "root_snap" created. >>> [root at lvmtest ~]# lvs >>> LV VG Attr LSize Pool Origin Data% Meta% Move >>> Log Cpy%Sync Convert >>> root centos owi-aos--- 2,93g >>> root_snap centos swi-a-s--- 2,94g root 0,00 >>> swap centos -wi-ao---- 1,00g >>> >>> --- reboot --- >>> >>> dracut shell (missing /dev/centos/root) >>> >>> cat proc/cmdline: >>> BOOT_IMAGE=/vmlinuz-3.10.0-229.20.1.el7.x86_64 >>> root=/dev/mapper/centos_root ro rd.lvm.lv=centos/root >>> rd.lvm.lv=centos/swap crashkernel=auto rhgb quiet LANG=de_DE.UTF-8 >>> systemd.debug >> >> shouldn't you have a new grub entry with: >> root=/dev/mapper/root_snap rd.lvm.lv=centos/root_snap >> >> Tru >> >> -- >> Tru Huynh >> http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xBEFA581B > > > > Gr??e > > Axel > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centosGr??e Axel
On 12/02/2015 12:05 PM, Axel Glienke wrote:> in journalctl i found: > modprobe: FATAL: Module dm-snapshot not found > ... > Can't process LV root_snap: snapshot target support missing from kernelI installed a very simple CentOS 7 system with an LVM root FS. Created a snapshot and rebooted, no problem. Updated dracut, then updated everything else and rebooted, no problem. As far as I can tell, dracut normally includes the entire kernel module tree under kernel/drivers/md, which should provide the dm-snapshot module required to complete the boot sequence. I can't determine what's causing the problem you see, but it doesn't appear to affect a standard installation. Try: dracut --force --debug > /var/tmp/dracut.txt 2>&1 Upload /var/tmp/dracut.txt to http://paste.fedoraproject.org/. I'll see if I spot anything useful.