From: justin corwin (email@example.com)
Date: Fri Aug 20 2004 - 13:26:49 MDT
Hi Peter ;-)
I've looked at these things before, and I'm posting publicly in case
it's useful for others.
>I'm looking for price & performance (access time) for:
prices vary a great deal based on what kind of support/branding you
need, and what you're willing to go through. I'll try to note relative
price points, where I have them.
>1) Cached RAID
RAID 0 is very fast with new hard drives, more than fast enough to
saturate a PCI bus. Even RAID 5 with SCSI or fast SATA drives(like the
10,000 RPM models begin to require PCI-X for full functionality.
with RAID 0 on a eight disk SATA array with Raptor 10,000 drives, your
possible throughput would be 480MB/s, there are some benchmarks
showing actual performance here:
price point for that setup is $1550, according to froogle.
>2) RAM disks
There are PCI card mounted RAM disky things, which I've seen used
before. Performance was not inspiring, topping out at 150 MB/s, and
very costly. Normal RAM prices, plus premiums for manufacturing. I
wouldn't recommend it. Those were a few years ago, and they may have
more intelligent controllers, bursting, etc, nowadays. Google
unfortunately doesn't return many hits on the subject.
>3) Internal RAM (using 64 bit architecture?)
there are opteron motherboards on the market right now that can mount
16 GB of memory with 2G chips. Windows can't mount the whole space, at
the moment, but expectations are high for a x86-64 version of windows
that can. If you wanted to be very expensive, there is an Itanium
version of windows, which may be able to mount large amounts of
internal RAM. I don't have any data on that.
there are of course, PowerMacs shipping with up to 8 GB of memory
directly from the Apple Store, which is interesting to see.
For this option, which isn't yet feasible, you see $650+ for each 2GB
dimm, and at least $350 for a motherboard with 8 slots. plus cpu
costs, attendant hardware, etc etc. which vary much.
If it doesn't have to be on the computer, there are network storage
solutions, many of which are very fast, requiring Fibre to keep up.
they are attendantly very very expensive.
tip top are things like RAM-SAN: http://www.superssd.com/products_sub.htm
more commodity esque, you have things like Apple's Xserv RAID, and
knockoffs. (a note, Xserv RAID will work in a windows environment, and
there are more.. wintel solutions available, if you want them, I'm
just not familiar, because they are either more expensive, or newer
than I've looked).
There are also nifty tricks you can do with a small network of
computers. in terms of building virtual disks out of internal ram, and
sharing them as network drives in arrays or with intermediate
controllers. This is a spooky and complicated subject, which Linux
probably has more solutions in. But I have old or unreliable
hope this is useful.
-- Justin Corwin firstname.lastname@example.org http://outlawpoet.blogspot.com
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