After having solved my raid5 creation problems, I'm running into a new one: the RAID is just impossible to mount through fstab. I get a wonderful "The disk drive for /dev/md0 is not ready yet or not present.
Continue to wait or press S to skip mounting or M for mount recovery."
Once the system has booted, I can perfectly run a mount /dev/md0 /media/raid and mount it manually.
I've already tried mdadm.conf with UUIDs, with device names, tried several options in fstab, xfs and ext4 filesystems, nothing to do, it won't mount.
All this is running under Ubuntu 10.04 server, kernel: 2.6.32-25 server, mdadm 3.1.4 (from a Debian sid)
Here's my mdadm.conf:
# Please refer to mdadm.conf(5) for information about this file.
# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes
# automatically tag new arrays as belonging to the local system
# instruct the monitoring daemon where to send mail alerts
# definitions of existing MD arrays
ARRAY /dev/md0 level=raid5 metadata=1.2 num-devices=3 devices=/dev/sda1,/dev/sdb1,/dev/sdd1
# This file was auto-generated on Tue, 02 Nov 2010 20:38:52 +0100
The entry in my fstab:
/dev/md0 /media/raid xfs defaults 0 0
and just for info, my /proc/mdstat:
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sda1 sdd1 sdb1
3907023872 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]
unused devices: <none>
Thanks for your help and patience!