Dell PE4600 RAID5 server failing

[Barnaby Scott]

I suspect I already know the answer to this, which is that the trouble I 
am having is nothing to do with the OS at all, but I have to ask, 
because I am otherwise up against a total brick wall!

I bought a second-hand Dell Poweredge 4600 and installed FreeBSD 6.2 
earlier this year. I had it set up with RAID5 using its PERC3/DC 
controller, with 7 x 73GB disks (+ 1 hot spare). So far so good, and it 
worked faultlessly as a Samba server for several months.

At the beginning of October, it went down, reporting a mismatch between 
the configuration on the NVRAM and the disks. With help from Dell 
support, I managed to recreate the RAID array and it worked again for a 
month.

In early November it happened again, and has kept happening since. At 
one point it appeared that the backplane was faulty, so I replaced that, 
but I cannot keep the server up for more than a day or so without this 
'mismatch' poblem.

What about diagnostics on the hardware you may ask? I have run all the 
diagnostic tools that Dell can supply - several times - and the server 
declares itself to be totally fault-free.

My specific questions therefore:

Is there any way at all that FreeBSD could be invloved with this 
problem? (I did notice for example that the Dell PERC3/DC controller was 
not in the list of supported hardware - but then again, why did it work 
for several months?)

Can I use FreeBSD to tell me anything about the fault that Dell's 
diagnostic tools haven't found?

(I do hope someone might be able to help - Dell are trying to get me to 
switch to a 'supported' OS!)


Thanks

Barnaby Scott