Hi,
I created a new software RAID 5 array with fresh hard disks. I used mkraid to generate the RAID array with four devices /dev/hdc1, /dev/hdd1, /dev/hdg1, and /dev/hdh1. I formatted the drives clean, usd mkfs to create ext3 filesystems on each, then used 'mkraid /dev/md0' to create the RAID. I then used the command 'mke2fs -j -b 4096 -R stride=16 /dev/md0' to create the filesystem on /dev/md0. I read somewhere that the chunk-size parameter in the /etc/raidtab file match the value of the block size multiplied by the stride value in the command above. The chunk-size in my /etc/raidtab file is 64. I then started the RAID using 'raidstart /dev/md0'. I was able to mount the partition correctly. However, when I tried to examine the status of the RAID array using mdadm, it showed /dev/hdg1 as being 'faulty removed'. I then hot added /dev/hdg1 to the array, and it started the rebuild process.
Today the array finished rebuilding, and all the hard drives seemed to be included in the RAID array. fsck also reported /dev/md0 to be clean. However, 'mdadm --detail --scan /dev/md0' shows the status as "Dirty".
Since, this didn't work as I had expected, I formatted my disks again, and tried using the following command to create the RAID array:
"mdadm -C /dev/md0 -c 64 -l raid5 -p left-symmetric -n 4 /dev/hdc1 /dev/hdd1 /dev/hdg1 /dev/hdh1".
This created the RAID array, but when I went to examine the array (mdamd -E /dev/md0), I still got an error:
"mdadm: No super block found on /dev/md0 (Expected magic a92b4efc, got 00000000)"
And 'mdadm --detail --scan /dev/md0' still returns the state of the array as 'dirty, degraded, recovering', and this time it is spare rebuilding /dev/hdh1.
What do the error messages mean?
Saurabh.
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