Software RAID creation failure - Device or resource busy

[acostoya]

Hello,

I've installed FC6 on a P-ATA disk and have 6 additional SATA disks to create a software RAID level 5. Motherboard is intel D975XBX with 8-SATA ports and Secondary controller is enabled on BIOS.

Installation goes OK. fdisk on /dev/sd{a,b,c,d,e,f} operates OK and I could repartition them with one Linux type partition, here

are two examples:

Disk /dev/sda: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1       38913   312568641   83  Linux



Disk /dev/sdc: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       38913   312568641   83  Linux

Anyway, when trying to create the 6-disk array with mdadmin I get to:

[root@NAS-1 ~]# mdadm -C -l5 -c64 -n5 -x1 /dev/md0 /dev/sd{a,b,c,d,e,f}1
mdadm: Cannot open /dev/sdc1: Device or resource busy
mdadm: Cannot open /dev/sdd1: Device or resource busy
mdadm: Cannot open /dev/sde1: Device or resource busy
mdadm: create aborted

Trying on the three disks that show no problem it creates, recover, makes filesystem and mounts OK.

[root@NAS-1 ~]# cat /proc/mdstat 
Personalities : [raid6] [raid5] [raid4] 
md0 : active raid5 sda1[0] sdf1[2] sdb1[1]
      625137152 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]
      
unused devices: <none>


[root@NAS-1 ~]# df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/hda3            232339168   3643248 216703400   2% /
/dev/hda1               147764     10800    129335   8% /boot
tmpfs                   969652         0    969652   0% /dev/shm
/dev/md0             615327224    202224 583868144   1% /nas1
fs:/nfs1             188108728 149031144  29522120  84% /nfs1

At this point trying to add a single (offending) disk returns the same error message:

[root@NAS-1 ~]# mdadm /dev/md0 -a /dev/sdc1
mdadm: Cannot open /dev/sdc1: Device or resource busy

[root@NAS-1 ~]# mdadm /dev/md0 -a /dev/sdd1
mdadm: Cannot open /dev/sdd1: Device or resource busy

[root@NAS-1 ~]# mdadm /dev/md0 -a /dev/sde1
mdadm: Cannot open /dev/sde1: Device or resource busy

The created disk spans over two different SATA controllers on the motherboard two on the first (ports 0 and port 1) and one on the second one (port 5).

I've planned this installations with two books, SAMS Fedora 5 unleashed and O'Reilly Managing RAID on Linux; but I'm not an expert and I've been trying to fix this for two days now without success.

Could you suggest what should I try?.

Best Regards,

Adrian Costoya