Erleuchteter,
I do NOT see any hdparm problems.
What I see is your kernel trying to recover from IDE lockup
Aug 27 08:04:11 hades kernel: hdg: DMA disabled
Aug 27 08:04:11 hades kernel: ide3: reset: successYour problems most likely stem from one of the following:
1. Your 2nd ide interface shares an IRQ with something else
2. Your 3rd IDE cable isn't 80pin and/or defective
3 Your 6th IDE drive happens to be old & slow, dying ?
To check have a look:
cat /var/log/dmesg.... look for your interfaces .. example ..
Probing IDE interface ide0...
hda: GCR-8483B, ATAPI CD/DVD-ROM drive
Using cfq io scheduler
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14.............................................
...look for errors concerning drives there ...
...........................................
[pls do
not post the whole stuff

]
Regards
Reinhold
For the rest:
http://wiki.contribs.org/Raid
...
# 4-6 Drives - Software RAID 5 + 1 Hot-spare
...
If you need to look check your raid with:
# cat /proc/mdstat
# mdadm --misc --detail /dev/md1
# mdadm --misc --detail /dev/md2