[KLUG Members] Re: RAID

[Adam Williams]

>>No, I think he meant "no matter what you use, make sure you have a
>>couple spares handy," which is obviously more important (safety) than
>>performance.
>Well, that too -- and I gathered that from the rest of his post.  But I
>wanted to point out the same thing that is available in cheap PCI cards
>are basically what you have on the mainboard.  If you have a Promise
>controller on your mainboard, you should be able to read its volumes
>with an equivalent series Promise "FastTrak" card.

"Should" is an important clause,  I've been bitten hard by lots of
"should"s in the past and am very skeptical.  Minor version numbers have
often rendered hardware components incompatible and reading the never
ending torrent of poorly written docs is just too much effort.  Out of
principle I avoid "integrated" components except for the most basic
(standard IDE, VGA for a console, etc...) uses.

>Furthermore, I also thought he was striving for the fact that one should
>stay away from the popular ATA RAID approach, especially with his
>preference for IBM i960-based SCSI RAID products. There is a _huge_
>difference in the design of "BIOS-less" ATA RAID and card that has an
>on-board, intelligent microcontroller, an embedded OS, DRAM buffer and
>4+ ATA channels proliferating the use of only _one_ device per channel.

Sure.  But my only experience is with SCSI.

ATA technology just doesn't interest me.  I find the price difference
for reasonable amounts of storage to be negligible, and one avoids all
the bizarre versions, hacks, workarounds, and lame products that come
with ATA.  I know what my SCSI card is,  I know it works with
99.999999999% of SCSI drives,  no magic cables required, etc....  Sure
you can't get a 10000TB SCSI drive at Best Buy for $19.95 + tax,  but 9
& 18 Gb drives are available cheap in abundance, and 36Gb aren't that
bad.  An IPS controller can be found for ~$50-$100, less than what some
ATA-RAID cards sell for.  And one can stack a bunch of drives up in an
external cabinet with dual P/S and four fans (~$150 on E-Bay).  Drive
failures?  I'm still using a cabinet full of 9Gb FH Seagate drives, and
they may still be spinning when I'm worm food.  They don't set any speed
records (but you might be surprised) but the majority of the crap on a
home system is totally insensitive to drive performance,  just put what
matters on fast/new drives (yawningly easy with LVM support) and
continue to use all the drives you've already paid for until the croak
(still waiting).

People love to toss around MTBF numbers, etc... but it is my significant
cumulative experience that ATA drives are disposable - in large part
maybe just because they have to be located in the same case as all the
other hot junk - unless one buys extra fans and drive bay coolers
and.... so the price differential is even further diminished.

I'm not interested in starting a SCSI/ATA holy way, people should use
whatever works for them.  Just saw my message being interpreted (which
is just fine) and thought I'd weigh in with my insight, knowledge,
ignorance, experience, prejudice, and general laziness.