Hi@akhtar,
You got this error because your command is not correct. You created your Logical Volume from your Volume Group. So you need to tell your Volume Group name as well. You can see the below command.
[root@localhost ~]# lvdisplay mylv
Volume group "mylv" not found
Cannot process volume group mylv
[root@localhost ~]# lvdisplay myvg/mylv
--- Logical volume ---
LV Path /dev/myvg/mylv
LV Name mylv
VG Name myvg
LV UUID yEPJZN-5Ucq-sL2u-VEKU-Nlpt-iTMh-HrH2uf
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2020-07-08 14:08:36 -0400
LV Status available
# open 0
LV Size 50.00 GiB
Current LE 12800
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:3
I hope this will solve your error.