/dev/sdb wierdness

[Andrew Lennon]

Hi,

Fresh install of FC6 x86_64 on NForce4 s939 AMD3500.

LVMs created fine on internal hda/hdb/hdc.  I then went to create for
SATA drives on sda,sdb, and sdc:

[root at selma ~]# fdisk /dev/sdb

xxxxxxx

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       30401   244196001   8e  Linux LVM

xxxxxxx

All fine there! Now the wierdness:

[root at selma ~]# pvcreate /dev/sdb1
  Device /dev/sdb1 not found (or ignored by filtering).

This was the 250GB drive.  I rebooted and swapped around the 3 drives
so now a 500GB was sdb and parititioned accordingly.

The problem remained.  Now the 500GB drive was not showing properly.
Putting the 500GB and 250GB back to original positions has allowed me
to create an LVM with sda1 and sdc1

 --- Physical volume ---
  PV Name               /dev/sda1
  VG Name               VGBackup
  PV Size               372.61 GB / not usable 3.56 MB
  Allocatable           yes (but full)
  PE Size (KByte)       4096
  Total PE              95387
  Free PE               0
  Allocated PE          95387
  PV UUID               CCcu72-34AO-q2lg-N3xw-s4O2-Ejry-RxD6ic

  --- Physical volume ---
  PV Name               /dev/sdc1
  VG Name               VGBackup
  PV Size               465.76 GB / not usable 1.50 MB
  Allocatable           yes (but full)
  PE Size (KByte)       4096
  Total PE              119234
  Free PE               0
  Allocated PE          119234
  PV UUID               zHYZV4-uj68-AYBF-mEFP-glmb-8167-d4fHcB

So I thought this might be LVM related.  I scrubbed the lot and went
with MDADM instead:

Disk /dev/sdb: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       30401   244196001   fd  Linux raid autodetect


but

[root at selma ~]# mdadm --create /dev/md0 /dev/sdb1 -n 1 -l 0 --force
mdadm: Cannot open /dev/sdb1: Device or resource busy
mdadm: create aborted


so no luck there:

Using a standard linux partition and ext2

Disk /dev/sdb: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       30401   244196001   83  Linux

 mkfs /dev/sdb1
mke2fs 1.39 (29-May-2006)
/dev/sdb1 is apparently in use by the system; will not make a filesystem here!

Making the drive sdc1 allows me to do everything as normal so the disk is OK


Any ideas?  It looks like something is hogging sdb1

Many thanks,

Andy