Anyone with more knowledge and experience, please correct me if I am wrong... However, according to my research, the superblock locations of a md array and of a Reiserfs filesystem are different.
For both ReiserFS and MD arrays, the superblock contains the metadata of the filesystem. The exact information that is kept and location differs for both filesystems.
According the info I read for Reiserfs, the superblock is the 16th block from the start of the disk, where the first 64k is kept for partition information/boot loader stuff.
The superblock location for an mdarray depends on the version of metadata it utilizes. All modern versions of mdadm utilize version 1.2 metadata by default. A 1.2v metadata superblock is located 4k from the beginning of the device.
I believe when you are quering /dev/sdc and /dev/sdd individually, the residual superblock data from reiserfs still exists, which is why you see the same data.
Unless you defined a different blocksize for your reiserfs disks, the default is 4k. As an experiment, you can try the following:
dd bs=4098 skip=64k count=1 if=/dev/zero of=/dev/sdc
And retry quering /dev/sdc and /dev/sdd to see if they still show as riserfs disks, i.e.
fsck -N /dev/sdc /dev/sdd
Also, the best way to determine if your raid 0 array is experiencing any benefit from striping is to perform a IO test to the array.
I recommend creating two files, /MediaFiles/test
and an abritrary test file on of of the non-raid disks, i.e. /home/test
and perform the following:
dd if=/dev/zero of=/home/test bs=1mb count=256
dd if=/dev/zero of=/MediaFiles/test bs=1mb count=256
Compare the times of the two IO tests. If the time for the 2nd test is signifiantly improved/faster than the first test, you'll know striping is in effect.
It is important to note however, that this is not a complete apples to apples test (more like gala apples and granny smith). The filesystem overhead will be different between you're /root partition and /MediaFiles, considering /root is still in RiserFS and /MediaFiles is in ext4.
Note: IO performance increases significantly for Raid array's when the block size is a multiple of the chunk size. I can't recall the sweet spot, but I remember you will get different results for different block sizes.
a. Linux MD Raid Wiki: https://raid.wiki.kernel.org/index.p...rblock_formats
b. ReiserFS: http://homes.cerias.purdue.edu/~flor...r/reiserfs.php