software raided linux box keeps hanging

[Keyser Soze]

My raid setup used to work fine, but just recently the system started
hanging.  And whenever redhat 7.2 is reinstalled, the system hangs minutes
later - sometimes even DURING the installation.

I tried to determine if the problem was the two raided disks, or the rest
of the PC.  So I moved just disks to another system, installed 7.2, raided
the disks the same way and the same symptoms appeared.

That tests seems to point towards the disks being faulty.  So I tried
testing the disks by installing 7.2 on them individually, without raiding
of course.  They work just fine.

So, all of that SEEMS to point towards an illegal partition setup.  The
setup includes two identical 40 GB drives.  The partitions of each disk
mirror each other, so they are physically identical.  For example:

disk 1:
/		(hda1 = 5 GB)
swap		(hda2 = 251 MB)
raid 1 w/ hdb3	(hda3 ~ 33 GB)

disk 2:
/var		(hdb1 = 5 GB)
/home		(hdb2 = 251 MB)
raid 1 w/ hda3	(hdb3 ~ 33 GB)

Is this a legal setup?  During boot up, there is a warning that there are
no spare disks.  But that shouldn't be the cause to the problem, right?  
I'm not sure what else check.  Is it illegal to just raid partitions such
this setup, rather than raiding the entire disks and using seperate a disk 
for swap, etc?