Calling ioctl() to re-read partition table.
Syncing disks.
[root@localhost ~]# mdadm -C -l raid1 -n2 /dev/md0 /dev/sdb1 /dev/sdb2 -x1 /dev/sdb3
mdadm: array /dev/md0 started.
[root@localhost ~]# mdadm -C -l raid1 -n2 /dev/md1 /dev/sdb5 /dev/sdb6 -x1 /dev/sdb7
mdadm: array /dev/md1 started.
[root@localhost ~]# df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1              3548036   2777468    587432  83% /
tmpfs                   257428         0    257428   0% /dev/shm
[root@localhost ~]# pvcreate /dev/md0 /dev/md1
  Writing physical volume data to disk "/dev/md0"
  Physical volume "/dev/md0" successfully created
  Writing physical volume data to disk "/dev/md1"
  Physical volume "/dev/md1" successfully created
[root@localhost ~]# vgcreate lab /dev/md0
  Volume group "lab" successfully created
[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               lab
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  1
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               288.00 MB
  PE Size               4.00 MB
  Total PE              72
  Alloc PE / Size       0 / 0
  Free  PE / Size       72 / 288.00 MB
  VG UUID               4aMApT-TPsi-JDDw-LGqU-1DpC-FswJ-U7lqwQ