CentOS

Greetings:

I have just installed CentOS 6.2 x64 on an IBM x3650 server with a QLogic 2462 dual port 4 gb fiber card. The card is direct connected to an IBM EXP810 chassis loaded with 6x 750 Gig SATA using SATA to FC adapter modules.

The drives are showing up just fine (though I do have to run partprobe after every boot for the partitions to show up).

[root@nas02 init.d]# mdadm --create /dev/md0 --chunk=256 --level=5 --raid-devices=6 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1
mdadm: cannot open /dev/sda1: No such file or directory
[root@nas02 init.d]# partprobe /dev/sda /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf
[root@nas02 init.d]# mdadm --create /dev/md0 --chunk=256 --level=5 --raid-devices=6 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1
mdadm: cannot open /dev/sda1: Device or resource busy

And yes, the disk is properly partitioned as RAID autodetect.

[root@nas02 init.d]# fdisk -l /dev/sda

Disk /dev/sda: 750.2 GB, 750156374016 bytes
255 heads, 63 sectors/track, 91201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb8e4f1a9

Device Boot Start End Blocks Id System
/dev/sda1 1 91201 732572001 fd Linux raid autodetect

Of course, no software RAID exists on the volumes yet.

[root@nas02 init.d]# cat /proc/mdstat
Personalities :
unused devices:

My question: what the heck am I doing wrong here? I can write to the disk without issue (via dd - zeroed out the beginning 40 Gig of the drives this way), I can read from the disk without issue (via hdparm -tT) but mdadm is somehow convinced that the volume is already in use somehow?

Ron

Found the problem.

There was apparently a DMRAID signature somewhere on a couple of the disks so DMRAID was capturing the disks and preventing MDADM from doing it's bit.

dmraid -an deactivated the DMRAID and allowed MDADM to work.

Thanks for letting me spew here!

Ron

Welcome to the CentOS fora. Please see the recommended reading for new users linked in my signature.

Thanks for reporting back. For the record that issue is covered in [url=http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5]Setup a Software RAID on CentOS 5[/url].

Marking this thread [SOLVED] for posterity.