Software RAID function of RH7.2 is not yet reliable.

On the RedHat7.2 IA-64 , 
The software RAID using the RH-OS command 
	( mkraid, raidstart, raidstop, /etc/raidtab, ...)
has a kernel drop problem when the raid disk is used (heavily?).

  I use Promise Ultra66 PCI IDE interface card , which has 2 IDE 
socket for the flat ribbon bus interface. (This is NOT a raid card 
in any means.)  I connected two ATA-100 compatible flat cables and 
put Maxtors 80GB UATA133 HDD on each cable as masters.  These HDD 
are recognized by the kernel as /dev/hde and /dev/hdg.

If these two HDD are used separately as the normal file systems or 
swap partitions, they are quite usable and works fine, and makes no 
trouble even the read/write or create/remove files are repeated 
heavily and many many times. It seems the HDD and IDE interface 
(and the kernel's driver software) are good.

I then built RAID0 or RAID1 as /dev/md0 from these two drives after
/etc/raidtab is written and mkraid is used and the created block 
device /dev/md0 can be "mkfs"ed to create the ext2 file system. 
That ext2 file system can be mounted like the usual file system as 
"mount /dev/md0 /mnt0".

In that file system, if I make or delete some files it seems to work fine.
But, if the large file is created using dd like:
	$ dd if=/dev/zero of=/mnt0/big-file obs=2000b 
or the creation of thousands of 1MB files in that directory using the 
shell script's while loop, then SUDDENLY the kernel drops without
any pre-sign and the FD or CD-ROM Drive lump flashes and seeks, and 
the system hangs at some status in the middle of the reboot process.
(I have to reset to make the reboot process to complete.) Note, the 
capacity is not reached at all. Typical drop points are as little
as serveral GB or even several hundres of MB.

I tried many times of this experiment, but the kernel drops always.
The drop point (the amount of file written before the kernel drop) 
is not always the same. Every trial, I made mkfs the /dev/md0 to
ext2 before the it was mounted.

It seems to me that the software RAID function of RH7.2 on IA-64 is 
not reliable yet.  If someone able to use the software RAID without 
this kind of trouble, I would like to hear what is the key of success.

H.M.