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 kernel
I 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.