vgdisplay shows no results, but lsblk shows partition

I have mounted a SAN 500 GB to /var. Due the power failure, the server tends to reboot and after reboot the mounted partition /var disappears. While checking with lsblk command it shows like.

vdb 254:16 0 500G 0 disk
└─vdb1 254:17 0 500G 0 part

instead of

vdb 254:16 0 500G 0 disk
└─vdb1 254:17 0 500G 0 part
└─DB-PGSQL 253:0 0 500G 0 lvm /var

Vgdisplay shows no details about DB(vgname).

Checked /etc/lvm, It having the details of the vgname and lvname.

How to recover the data and remount the LVM like earlier. Please help