# lvcreate -L100G -n bb-snapshot -s  virt/bb
#kpartx -a /dev/mapper/virt-bb #Т.е. на диске несколько 
разделов

# lvdisplay
--- Logical volume ---
  LV Name                /dev/virt/bb
  VG Name                virt
  LV UUID                v1eZ1H-MyJG-RFiD-oN3R-9n6n-QF0a-D0KjSs
  LV Write Access        read/write
  LV snapshot status     source of
                         /dev/virt/bb-snapshot [INACTIVE]
  LV Status              available
  # open                 1
  LV Size                15.00 GiB
  Current LE             3840
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           251:13
   
    --- Logical volume ---
  LV Name                /dev/virt/bb-snapshot
  VG Name                virt
  LV UUID                gr3Ck9-PCdb-qMhA-Uhfp-q86o-j4P2-PDHENZ
  LV Write Access        read/write
  LV snapshot status     INACTIVE destination for /dev/virt/bb
  LV Status              available
  # open                 3
  LV Size                15.00 GiB
  Current LE             3840
  COW-table size         17.00 GiB
  COW-table LE           4352
  Snapshot chunk size    4.00 KiB
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           251:16

# lvs
  /dev/dm-16: read failed after 0 of 4096 at 0: Input/output error
  /dev/dm-19: read failed after 0 of 4096 at 0: Input/output error
  /dev/dm-21: read failed after 0 of 4096 at 0: Input/output error
  /dev/dm-22: read failed after 0 of 4096 at 0: Input/output error
  LV                     VG     Attr   LSize   Origin        Snap%  Move Log Copy%  Convert
  virt-bb          iserv  owi-ao  15.00g                                             
  virt-bb-snapshot iserv  Swi-Io  17.00g virt-bb 100.00

# lvremove -f virt/bb-snapshot. 
  /dev/dm-16: read failed after 0 of 4096 at 0: Input/output error
  /dev/dm-19: read failed after 0 of 4096 at 0: Input/output error
  /dev/dm-21: read failed after 0 of 4096 at 0: Input/output error
  /dev/dm-22: read failed after 0 of 4096 at 0: Input/output error
  Can't remove open logical volume "virt-bb-snapshot"
# kpartx -v -d /dev/virt/bb-snapshot 
read error, sector 0
read error, sector 1
read error, sector 29

kpartx -a /dev/virt/disk
mount /dev/mapper/virt-disk1 /mnt
mount -t proc none /mnt/proc/
mount -o bind /dev/ /mnt/dev/
chroot /mnt/ /bin/bash
update-grub
grub-install /dev/mapper/virt-disk