I had raid 5 for data, with 3 disks: /dev/sdb /dev/sdc /dev/sdd.
Also there is a system disk /dev/sda.
I add another system disk that become /dev/sdb so the raid disks become /dev/sdc /dev/sdd /dev/sde.
Since the raid disk didn't start I made a mistake and try to assemble the raid with the previous configuration:
echo 'DEVICE /dev/sdb /dev/sdc /dev/sdd' > mdadm.conf
mdadm --examine --scan --config=mdadm.conf >> mdadm.conf
mdadm -A --scan
Immediately after that I understood what I did and now I try to fix it.
Now the situation is that I have the raid but can't mount it:
# mdadm -D /dev/md0
Version : 0.90
Creation Time : Wed Aug 27 19:35:26 2008
Raid Level : raid5
Array Size : 625142272 (596.18 GiB 640.15 GB)
Used Dev Size : 312571136 (298.09 GiB 320.07 GB)
Raid Devices : 3
Total Devices : 3
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Thu Jan 29 06:05:11 2009
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
UUID : ce1bae3d:532e86e3:14e9d8a5:05270762
Events : 0.28
Number Major Minor RaidDevice State
0 8 32 0 active sync /dev/sdc
1 8 16 1 active sync /dev/sdb
2 8 48 2 active sync /dev/sdd
# mount /dev/md0 /mnt/RaidData/
mount: wrong fs type, bad option, bad superblock on /dev/md0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
Can anyone help me before I do something wrong.