Re: SCSI disk: still the way to go?

Compare these two drives:

http://www.storagereview.com/php/benchmark/suite_v4.php?typeID=10&testbedID=4&osID=6&raidconfigID=1&numDrives=1&devID_0=279&devID_1=308&devCnt=2

Prices:

http://www.cdw.com/shop/products/default.aspx?EDC=984588 - SAS - ~$950
http://www.cdw.com/shop/products/default.aspx?EDC=912784 SATA - ~$320

For a third of the price you can have 90% of the throughput performance,
which is probably where you will be most stressing your drives in a data
warehouse.

I have only seen good benchmarks from LSI's MegaRAID controllers for SCSI in
linux, I have seen good results from LSI, 3Ware (now AMCC) and Areca in
Linux for their SATA products (in RAID 10). There are plenty of large drive
number chasis out there with SATA hot swap bays if you want them. Tyan
makes a great dual CPU board with two independant PCI-X buses. that will
give 1066MB/sec total through put each which I have great benchmark number
from.

it's possible to reach these numbers with SAN, but it will cost major major
$$s. Each FC line in a SAN is typically 2Gb last time I checked, so you
need multiple channels to acheive a max of 1066MB/sec throughput per PCI-X
bus. If you run the numbers, you theoretically need 24 drives in a RAID 10
to get max throughput (Areca makes a 24 channel SATA card:
http://www.newegg.com/Product/Product.asp?Item=N82E16816151004 - Although I
couldn't find one with multilane support). I have seen chassis that can
hold 40 drives. If you go for the 74Gig cousin that has similar throughput,
which you can get OEM for $160/each you are talking just about $6400 in
drives, plus about $4k for the chasis (
http://rackmountmart.stores.yahoo.net/rm8uracchasw.html), plus about $5k for
other components (depending on RAM/CPU), so a massively kick ass whitebox
can be had for about $16k that will acheive close to the maximum theoretical
throughput acheivable in a single server for MB/sec.

Now there are arguments to be had about splitting up table spaces etc, but I
present this as a concrete example of components that can be had for not
alot of money to build a majorly kick ass server using SATA technology.

Alex

On 5/30/06, Ben <bench(at)silentmedia(dot)com> wrote:
>
> How much money do you want to spend? If you don't care, SAN is probably
> the way
> to go.
>
> How much data do you have to store? If you can afford to fit it onto scsi,
> scsi
> probably is still the way to go.
>
> Otherwise, sata arrays have come a long way in 3 years, and they are by
> FAR the
> cheapest solution out there. Do some research and see if they're good
> enough for
> you.
>
> On Tue, 30 May 2006, Riccardo Inverni wrote:
>
> > Hi guys,
> >
> > I have to update a Linux box with PostgreSQL on it, essentially for
> data
> > warehousing purposes. I had set it up about 3 years ago and at that time
> the
> > best solution I had been recommended was to use SCSI disks with hardware
> > RAID controllers.
> >
> > Is this still the way to go or things have recently changed? Any other
> > suggestion/advice? What about SAN?
> >
> > Thanks.
> >
> > Cheers,
> > Riccardo
> >
>
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