[CentOS] lvm snapshot

Wed Dec 2 20:05:40 UTC 2015
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



Grüße

Axel