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@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@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@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