What I think he is missing here is: "What is the cost of lost data?"

He sees a cost of installing RAID systems for customers as increased support
calls. Without RAID, he has only a fraction of the support calls and if a HD
actually breaks, he replaces the drive (no cost as it is warranted by the mfg),
and does re-install of the OS and apps he originally installed and he's done. So
what if the customer just lost a bunch of valuable data? The occasional failure
costs him maybe 3-4 hours of tech time.

No cost is assigned to the data that is lost, or additional software that has
been installed and configured since the customer bought the machine. The cost of
the data lost can be from nearly zero (high scores on a couple of games) to HUGE
(a company's complete accounting system, the novel you just wrote, the images
from a professional photo-shoot, the PCB design and code for a product, all of
the above, etc). 

In my mind (I'm obviously an old IT guy whose experience goes way back to
mainframe days), the data on the system is the only thing of real value and
anything that reduces the chance of data loss is a good thing. 

Additional complexity? A RAID system is more complex than no RAID, but it is
automated and always backing up your data. A backup plan is also complex, with
many more human based things that can go wrong (forgot to do it for the last
month, staff changed a year ago and didn't know they were supposed to do it, "I
thought that message was normal - its been happening for over a year.", etc).

I think RAID-1 systems (mirroring) are pretty good for protecting against
hardware failure in the drives. RAID-0 (striping or volume concatenation) is a
dangerous thing that must be considered carefully for actively modified or
valuable data. RAID-5 can be good if you have a high-end RAID controller with
non-volatile memory - otherwise the write performance can be dismal, and the
risk of data loss significant.

-----Original Message-----
From: piclist-bounces@MIT.EDU [mailto:piclist-bounces@MIT.EDU] On Behalf Of
Apptech
Sent: Sunday, February 24, 2008 12:54 AM
To: PIC List
Subject: [EE]:: Whr R.A.I.D. is a terrible idea

He argues that RAID typically reduces reliability.
ie done well it can be an improvement, but ... . 
 
Makes some sense.
What do others think

    http://www.pugetsystems.com/articles?&id=29
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