Physical volume disappeared on reboot - help!

Any guidance appreciated...

RHEL on VMware, added a new 1.4TB virtual disk a few weeks ago, created a new PV, logical volume and volume group, mounted it at /var/www/vhosts/mountpoint, and all was good.

Server rebooted this morning, and won't start. Have removed new mount point from /etc/fstab and it starts fine.

No sign of my VG, LV or PV! Argggh... Device is connected in VMWare and visible as /dev/sdc.

(It was in a VG called vg_vhosts_stmacks)

[root@callisto ~]# lvmdiskscan
/dev/sda1 [ 600.00 MiB]
/dev/sda2 [ 1.00 GiB]
/dev/sda3 [ 78.00 GiB] LVM physical volume
/dev/sdb1 [ 140.00 GiB] LVM physical volume
/dev/sdb2 [ 360.00 GiB] LVM physical volume
/dev/sdc [ 1.37 TiB]
1 disk
2 partitions
0 LVM physical volume whole disks
3 LVM physical volumes

[root@callisto ~]# vgs
VG #PV #LV #SN Attr VSize VFree
vg_system 1 2 0 wz--n- 78.00g 4.00m
vg_vhosts 2 1 0 wz--n- 499.99g 0

[root@callisto ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
root vg_system -wi-ao---- 70.00g
swap vg_system -wi-ao---- 8.00g
var_www_vhosts vg_vhosts -wi-ao---- 499.99g

[root@callisto ~]# vgscan --cache
Found volume group "vg_vhosts" using metadata type lvm2
Found volume group "vg_system" using metadata type lvm2

What next?!