LVM2 : Failing to pvcreate a block device

Question

I'm trying to make use of the LVM2 functionality in linux (Centos6.0). When trying to make the first step of defining a PV on a specific block device, I get the following error message:

[root@localhost /] pvcreate /dev/sdb

Can't open /dev/sdb exclusively. Mounted filesystem?

/dev/sdb is not mounted and its partition table was deleted. I should mention also that /dev/sdb used to represent a larger block device (about 4 times larger) and was reduced by configuration of hardware raid (I split the hd to 4 in the raid controller).

Has anyone ever encountered this error before and knows how to take it from here?

Answer 1

[root@localhost /] pvcreate -vvvvv /dev/sdb

Could ouput more details. and you could use lsof -L to check if the block device is opened by other process.

Answer 2

Maybe device-mapper is 'stealing' this device. Try this:

[root@host ~]# dmsetup ls
sdb     (253, 2)
VolGroup00-LogVol01     (253, 1)
VolGroup00-LogVol00     (253, 0)

If you find sdb device listed as above example, remove it using dmsetup and create the physical volume:

[root@host ~]# dmsetup remove sdb

[root@host ~]# pvcreate /dev/sdb
Physical volume "/dev/sdb" successfully created