After an ok upgrade with yum to FC6 I can't seem to get a RAID 0 that was on the box to work.
Note it was /dev/md1 but I have changed the configs to /dev/md0 and it was all working before the upgrade
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[root@mitsuhama ~]# mdadm -A -v /dev/md0 /dev/sdc /dev/sdd
mdadm: looking for devices for /dev/md0
mdadm: cannot open device /dev/sdc: Device or resource busy
mdadm: /dev/sdc has no superblock - assembly aborted
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[root@mitsuhama ~]# mdadm -E /dev/md0
mdadm: No md superblock detected on /dev/md0.
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[root@mitsuhama ~]# mdadm -E /dev/sdc
/dev/sdc:
Magic : a92b4efc
Version : 00.90.03
UUID : 393aace8:7dea2e17:5f9a3258:a5258030
Creation Time : Tue Aug 29 13:26:35 2006
Raid Level : raid0
Device Size : 195360896 (186.31 GiB 200.05 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0

Update Time : Tue Aug 29 13:26:35 2006
State : active
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : fa9d7618 - correct
Events : 0.1

Chunk Size : 64K

Number Major Minor RaidDevice State
this 0 22 0 0 active sync

0 0 22 0 0 active sync
1 1 22 64 1 active sync
----------------------

[root@mitsuhama ~]# mdadm -E /dev/sdd
/dev/sdd:
Magic : a92b4efc
Version : 00.90.03
UUID : 393aace8:7dea2e17:5f9a3258:a5258030
Creation Time : Tue Aug 29 13:26:35 2006
Raid Level : raid0
Device Size : 195360896 (186.31 GiB 200.05 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0

Update Time : Tue Aug 29 13:26:35 2006
State : active
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : fa9d765a - correct
Events : 0.1

Chunk Size : 64K

Number Major Minor RaidDevice State
this 1 22 64 1 active sync

0 0 22 0 0 active sync
1 1 22 64 1 active sync