I'm confused. What exactly are you trying to do here? I can't think of any reason why you would want to copy a snapshot lv to a file then try to loop mount it. Tomas Dalebjörk <tomas.dalebjork@xxxxxxxxx> writes: > Hi, > > I am trying to understand how to convert a disk containing snapshot data. > This is how I tested this: > 1. locate the snapshot testlv.211218.232255 > root@debian10:/dev/mapper# lvs > LV VG Attr LSize Pool Origin Data% > Meta% Move Log Cpy%Sync Convert > home debian10-vg -wi-ao---- 1.00g > root debian10-vg -wi-ao---- <3.81g > swap_1 debian10-vg -wi-ao---- 976.00m > testlv debian10-vg owi-aos--- 100.00m > testlv.211218.232255 debian10-vg swi-a-s--- 104.00m testlv 1.44 > root@debian10:/dev/mapper# > > 2. copy the lv - cow data to a file > # dd if=/dev/mapper/debian10--vg-testlv.211218.232255-cow of=/tmp/out > bs=1024 > > 3. Setup a loopback disk for the file > # losetup -fP /tmp/out > > 4. Verify that disk exists > root@debian10:/dev/mapper# losetup -a > /dev/loop0: [65025]:39274 (/tmp/out) > root@debian10:/dev/mapper# > > 5. Try converting the disk using lvconvert command > # lvconvert -Zn -s debian10-vg/testlv /tmp/out > "/tmp/out": Invalid path for Logical Volume. > > 6. Trying creating a softlink in /dev/mapper > # ln -s /tmp/out debian10--vg-loopback > > 7. verify link > root@debian10:/dev/mapper# ls -la > total 0 > drwxr-xr-x 2 root root 240 Dec 19 17:40 . > drwxr-xr-x 18 root root 3820 Dec 19 17:22 .. > crw------- 1 root root 10, 236 Dec 10 19:10 control > lrwxrwxrwx 1 root root 7 Dec 10 19:10 debian10--vg-home -> ../dm-5 > lrwxrwxrwx 1 root root 8 Dec 19 17:40 debian10--vg-loopback -> > /tmp/out > lrwxrwxrwx 1 root root 7 Dec 13 22:20 debian10--vg-root -> ../dm-1 > lrwxrwxrwx 1 root root 7 Dec 10 19:10 debian10--vg-swap_1 -> ../dm-4 > lrwxrwxrwx 1 root root 7 Dec 18 23:23 debian10--vg-testlv -> ../dm-0 > lrwxrwxrwx 1 root root 7 Dec 18 23:23 > debian10--vg-testlv.211218.232255 -> ../dm-6 > lrwxrwxrwx 1 root root 7 Dec 18 23:23 > debian10--vg-testlv.211218.232255-cow -> ../dm-3 > lrwxrwxrwx 1 root root 7 Dec 18 23:23 debian10--vg-testlv-real -> > ../dm-2 > root@debian10:/dev/mapper# > > 8. retrying lvconvert command > root@debian10:/dev/mapper# lvconvert -Zn -s debian10-vg/testlv > /dev/mapper/debian10--vg-loopback > Failed to find logical volume "debian10-vg/loopback" > root@debian10:/dev/mapper# > > Are there more things to be considered, such as recreating pv data on disk? > > Regards Tomas > _______________________________________________ > linux-lvm mailing list > linux-lvm@xxxxxxxxxx > https://listman.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
