Problem with raidframe: bad disk or bad memory, how to tell?

[buhrow%lothlorien.nfbcal.org@localhost (Brian Buhrow)]

        Hello.  I have a NetBSD-3.1 system in production which seems to be
experiencing a filesystem issue on its raid1 root partition.  The symptoms
are that when we tried to run a backup last night, the dump program never
completed, and it created an endless dump file.  Also, running fsck on the
root partition yields inconsistent results, especially when you consider
that this machine isn't that active.
        I think that either one of the disks is silently corrupting data,
or I have some bad memory in the box.  I'm almost certain it's a hardware
issue, but the question is, how to tell which hardware specifically is the
problem?  I could try failing one of the disks, but then, if I pick the
wrong one, I'm really in trouble.  Is there some utility I can use to
compare the contents of the two disks to see if they're equal?  the box is
a production box, as I mentioned, so I'd like to avoid bouncing it up and
down, at least until I've figured out what  the problem is most likely to
b.
        Any thoughts?
-thanks
-Brian


sCRIPT STarted on Thu Jul 10 14:21:19 2008
pbx# fsck /dev/rraid0a
** /dev/rraid0a
** Last Mounted on /
** Root file system
** Phase 1 - Check Blocks and Sizes
UNKNOWN FILE TYPE I=1480576
CLEAR? [yn] ^C
pbx# !!
fsck /dev/rraid0a
** /dev/rraid0a
** Last Mounted on /
** Root file system
** Phase 1 - Check Blocks and Sizes
UNKNOWN FILE TYPE I=2310400
CLEAR? [yn] ^C
pbx# !!
fsck /dev/rraid0a
** /dev/rraid0a
** Last Mounted on /
** Root file system
** Phase 1 - Check Blocks and Sizes
UNKNOWN FILE TYPE I=3544080
CLEAR? [yn] ^C
pbx# !!
fsck /dev/rraid0a
** /dev/rraid0a
** Last Mounted on /
** Root file system
** Phase 1 - Check Blocks and Sizes
UNKNOWN FILE TYPE I=6021376
CLEAR? [yn] ^C
pbx# !!
fsck /dev/rraid0a
** /dev/rraid0a
** Last Mounted on /
** Root file system
** Phase 1 - Check Blocks and Sizes
UNKNOWN FILE TYPE I=3122884
CLEAR? [yn] ^C
pbx# exit
Script done on Thu Jul 10 14:24:00 2008