Adding a LVM Cinder Volume

 

mkfs.ext /dev/md0
mkdir /cinder-vol
mount /dev/md0 /cinder-volumes
dd if=/dev/zero of=/cinder-vol/cinder-vol bs=1 count=0 seek=3950G
losetup /dev/loop2 /cinder-vol/cinder-vol
pvcreate /dev/loop2
vgcreate cinder-vol /dev/loop2

Double check your work with pvdisplay and vgdisplay:

 [root@openstack ~]# pvdisplay
 --- Physical volume ---
 PV Name /dev/loop2
 VG Name cinder-vol
 PV Size <3.86 TiB / not usable 4.00 MiB
 Allocatable yes
 PE Size 4.00 MiB
 Total PE 1011199
 Free PE 1011199
 Allocated PE 0
 PV UUID HwHPNB-48pG-igg4-EU7d-Rucj-vniF-lrYP22

[root@openstack ~]# vgdisplay
 --- Volume group ---
 VG Name cinder-vol
 System ID
 Format lvm2
 Metadata Areas 1
 Metadata Sequence No 1
 VG Access read/write
 VG Status resizable
 MAX LV 0
 Cur LV 0
 Open LV 0
 Max PV 0
 Cur PV 1
 Act PV 1
 VG Size <3.86 TiB
 PE Size 4.00 MiB
 Total PE 1011199
 Alloc PE / Size 0 / 0
 Free PE / Size 1011199 / <3.86 TiB
 VG UUID ILuHCP-9822-V1GS-lMu7-eiRu-UD3S-9xqDwY

vim /etc/cinder/cinder.conf

[lvm]
volume_backend_name=lvm
volume_driver=cinder.volume.drivers.lvm.LVMVolumeDriver
iscsi_ip_address=192.168.2.57
iscsi_helper=lioadm
volume_group=cinder-vol
volumes_dir=/cinder-vol/cinder-vol

systemctl restart openstack-cinder-scheduler
systemctl restart openstack-cinder-volume