Very interesting problem. My mail server (Debian Sarge) raid array broke. At first this does not seem very odd BUT their does not seem to be anything wrong with the partition. I ran a fsck.ext3 on it and it comes up with 0 errors yet it will not join the array. This is raid1. One of the drives is a partition and the other is a stand alone drive.
Has anyone seen this before and if so have any ideas on how to get it to join the array?
# e2fsck -nvf /dev/hda3
e2fsck 1.37 (21-Mar-2005)
Warning! /dev/hda3 is mounted.
Warning: skipping journal recovery because doing a read-only filesystem check.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
207149 inodes used (2%)
21176 non-contiguous inodes (10.2%)
# of inodes with ind/dind/tind blocks: 30519/409/0
3890435 blocks used (26%)
0 bad blocks
0 large files
204782 regular files
0 character device files
0 block device files
4 symbolic links (4 fast symbolic links)
Personalities : [raid1]
md0 : active raid1 hdc3
58119680 blocks [2/1] [_U]
unused devices: <none>
ide0: BM-DMA at 0xffa0-0xffa7, BIOS settings: hda
ide1: BM-DMA at 0xffa8-0xffaf, BIOS settings: hdc
hda: WDC WD800JB-00JJC0, ATA DISK drive
hda: max request size: 128KiB
hda: 156301488 sectors (80026 MB) w/8192KiB Cache, CHS=65535/16/63, UDMA(100)
hdc: WDC WD800JB-00JJC0, ATA DISK drive
hdc: max request size: 128KiB
hdc: 156301488 sectors (80026 MB) w/8192KiB Cache, CHS=65535/16/63, UDMA(100)
Adding 499928k swap on /dev/hda1. Priority:-1 extents:1
Adding 499928k swap on /dev/hdc1. Priority:-2 extents:1
EXT3 FS on hda2, internal journal
md: kicking non-fresh hda3 from array!
EXT3 FS on hda3, internal journal