Re: SCSI vs SATA - Mailing list pgsql-performance

BE VERY WARY OF USING AN ADAPTEC RAID CONTROLLER!

IME, they are usually the worst of the commodity RAID controllers available.
I've often seen SW RAID outperform them.

If you are going to use this config, Tyan's n3600M (AKA S2932) MB has
a variant that comes with 8 SAS + 6 SATA II connectors.
The SKU is S2932WG2NR.
http://www.tyan.us/product_board_detail.aspx?pid=453

Be very careful to get this =exact= SKU if you order this board and
want the one with SAS support.
The non-SAS variant's SKU is S2932G2NR.  Note that the only
difference is the "W" in the middle.

Anyway, the onboard RAID is based on a LSI PCI-E controller.

I'm using this beast (Dual Socket F, AMD Barcelona ready, 16 DIMMS
supporting up to 64GB of ECC RAM, 2 PCI-Ex16 slots w/ PCI-Ex8 signalling, etc:
~$450 US w/o SAS, ~$500 US w/ SAS) for my most recent pg 8.2.3 build
on top of XFS.

If the on board RAID is or becomes inadequate to your needs, I'd
strongly suggest either 3ware or Areca RAID controllers.

Side Note:
What kind of HDs are the 8*73GB ones?  If they are the new 2.5"
Savvio 15Ks, be =VERY= careful about having proper power and cooling for them.
14 HD's in one case are going to have a serious transient load on
system start up and (especially with those SAS HDs) can generate a
great deal of heat.

What 16bay 3U server are you using?

Cheers,
Ron Peacetree

PS to all:  Tom's point about the difference between enterprise and
and non-enterprise HDs is dead on accurate.
Enterprise class HD's have case "clam shells" that are specifically
designed for 5 years of 24x7 operation is gangs of RAID under typical
conditions found in a reasonable NOC.
Consumer HDs are designed to be used in consumer boxes in "one's and
two's", and for far less time per day, and under far less punishment
during the time they are on.
There is a =big= difference between consumer class HDs and enterprise
class HDs even if they both have 5 year warranties.
Buy the right thing for your typical use case or risk losing company data.

Getting the wrong thing when it is your responsibility to get the
right thing is a firing offense if Something Bad happens to the data
because of it where I come from.


At 07:42 PM 4/4/2007, jason@ohloh.net wrote:
>In a perhaps fitting compromise, I have decide to go with a hybrid
>solution:
>
>8*73GB 15k SAS drives hooked up to Adaptec 4800SAS
>PLUS
>6*150GB SATA II drives hooked up to mobo (for now)
>
>All wrapped in a 16bay 3U server. My reasoning is that the extra SATA
>drives are practically free compared to the rest of the system (since
>the mobo has 6 onboard connectors). I plan on putting the pg_xlog &
>operating system on the sata drives and the tables/indices on the SAS
>drives, although  I might not use the sata drives for the xlog if
>they dont pan out perf-wise. I plan on getting the battery backed
>module for the adaptec (72 hours of charge time).
>
>Thanks to everyone for the valuable input. I hope i can do you all
>proud with the setup and postgres.conf optimizations.
>
>-jay
>
>
>On Apr 4, 2007, at 1:48 PM, Carlos Moreno wrote:
>
>>
>>>Problem is :), you can purchase SATA Enterprise Drives.
>>
>>Problem????  I would have thought that was a good thing!!!   ;-)
>>
>>Carlos
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