connect() failed on local socket: No such file or directory Internal cluster locking initialisation failed. WARNING: Falling back to local file-based locking. Volume Groups with the clustered attribute will be inaccessible.

If the you get the message,

Check if the clvmd process is running.

If not start the process.

[root@node1 /]# service clvmd start
Starting clvmd:
Activating VG(s):   2 logical volume(s) in volume group "VolGroup" now active
  clvmd not running on node node2
                                                           [  OK  ]
[root@node1 /]#

[root@node1 /]# pvs
  PV                 VG       Fmt  Attr PSize PFree
  /dev/mapper/oracle          lvm2 a--  1.00g 1.00g
  /dev/sda2          VolGroup lvm2 a--  7.51g    0
[root@node1 /]#