mdadm –assemble /dev/md0 /dev/sdb1
mdadm: /dev/md0 has been started with 1 drive (out of 2).

pvscan
PV /dev/md0 VG host lvm2 [1,36 TB / 580,86 GB free]
Total: 1 [1,36 TB] / in use: 1 [1,36 TB] / in no VG: 0 [0 ]

vgscan
Reading all physical volumes. This may take a while…
Found volume group „host” using metadata type lvm2

cat /proc/mdstat
Personalities : [raid1]
md0 : active (auto-read-only) raid1 sdb1[1]
1465135936 blocks [2/1] [_U]

mdadm –readwrite /dev/md0

lvscan
inactive ‚/dev/host/swap’ [2,93 GB] inherit
inactive ‚/dev/host/root’ [29,30 GB] inherit
inactive ‚/dev/host/home’ [781,25 GB] inherit
inactive ‚/dev/host/tmp’ [2,93 GB] inherit

lvdisplay /dev/host/tmp
— Logical volume —
LV Name /dev/host/tmp
VG Name host
LV UUID xY3Q6E-3LNG-Qw49-UXMo-wryK-7Vm4-W2Aulh
LV Write Access read/write
LV Status NOT available
LV Size 2,93 GB
Current LE 750
Segments 1
Allocation inherit
Read ahead sectors auto

vgchange -a y host

ACTIVE ‚/dev/host/swap’ [2,93 GB] inherit
ACTIVE ‚/dev/host/root’ [29,30 GB] inherit
ACTIVE ‚/dev/host/home’ [781,25 GB] inherit
ACTIVE ‚/dev/host/tmp’ [2,93 GB] inherit

lvdisplay /dev/host/tmp

LV Name /dev/host/tmp
VG Name host
LV UUID xY3Q6E-3LNG-Qw49-UXMo-wryK-7Vm4-W2Aulh
LV Write Access read/write
LV Status available
# open 0
LV Size 2,93 GB
Current LE 750
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:3

Po pracy:
lvchange -a n host
mdadm –stop /dev/md0