pvcreate Can’t open /dev/sda exclusively. Mounted filesystem?

[root@localhost client]# pvcreate /dev/sda
  Can't open /dev/sda exclusively.  Mounted filesystem?
  Can't open /dev/sda exclusively.  Mounted filesystem?

[root@localhost client]# mount | grep /dev/sda
[root@localhost client]# 

[root@localhost client]# fuser -m -v /dev/sda1
[root@localhost client]#

[root@localhost client]# cat /proc/mdstat 
Personalities : 
md127 : inactive sda[0](S)
      1875243352 blocks super 1.2

[root@localhost client]# mdadm --stop /dev/md127
mdadm: stopped /dev/md127

[root@localhost client]# cat /proc/mdstat 
Personalities : 
unused devices: <none>

[root@localhost client]# mdadm --zero-superblock /dev/sda
[root@localhost client]#