RE: [suse-amd64] IBM or Tyan
Yes, U320 SCSI is WAY,WAY faster that SATA. That is my experience using Java web applications.
This is not a pure U320 SCSI versus SATA comparison. But on our production server with U320 SCSI, Intel RAID controller and 3 x
15000 rpm drives, database queries are almost 5 to 10 times faster than on a workstation with single SATA drive. The SCSI is in a
minimal RAID-5 configuration (i.e. only 3 disks). The production server has dual Opteron 240 chips (1.4Ghz), the test box has an AMD
Athlon 2500 (about 2Ghz).
First, the scsi bus can handle IO to multiple disks at one time.
Second you've got (usually one) 320MHZ bus versus a 150MHZ bus.
True, each SATA drive has 150MHZ.
Third,I would imagine, there has been a lot more time and money invested in optimizing drivers for the SCSI controllers, otherwise
folks would not buy them.
SCSI is expensive, but not that much more expensive than the equivalent SATA equipment. SATA's costs can be deceiving.
To get drives of the same caliber as SCSI drives you have to go to the Western Digital Raptor drives - they spin at 10,000 rpm - a
74MB drive is about US $206. A similar drive in U320 SCSI is about US $256, but you can also get a 15000 rpm drive for about US
$500.
The inexpensive BIOS/software RAID chips (card or motherboard) have no processor chip and no RAM CACHE. They simply do not compare
performance-wise to real hardware RAID. Actually Linux software RAID usually performs better than the RAID drivers that these chips
come with - there are a number of posts that have the results to prove this.
However a good SATA RAID controller with its own CPU and RAM is not really cheaper for SATA then SCSI. A 3Ware 8506-4LP SATA RAID
controller costs about US $340, the 8506-8LP costs about US $500. Adaptec U320 SCSI RAID controller are around US $400 for a single
channel card and about US $600 for a dual channel card (2 SCSI busses that can handle 15 devices each).
I am sure there's someone with more precise technical data, but I hope this helps.
If you need performance and you can affort the incremental costs, go SCSI.
- Richard
-----Original Message-----
From: rrpalma@synopsis.ws [mailto:rrpalma@synopsis.ws]
Sent: Tuesday, June 01, 2004 8:32 AM
To: skarsch@s1.karsch-net.de
Cc: Richard Mixon (qwest); suse-amd64@suse.com
Subject: RE: [suse-amd64] IBM or Tyan
Hello Don,
Thanks for your reply.
You're absolutely right; that's the IBM I'm referring to. What memory
are you using on your S2885? Please pardon my ignorance, but is it right
to assume that U320 SCSI is faster than SATA?
Regards,
_____________________________
Ricardo R Palma
SYNOPSIS SA
Tel. (+51 1) 275-7523, 275-4708
email: rrpalma@synopsis.ws
www.synopsis.ws
"Pettini, Don"
Hello Richard,
Thank you very much for your detailed and helpful explanation.
We're still in the midst of deciding whether to go for the Intellistation
A Pro (with its SCSI drives), but Opteron's 248 or the Tyan based machine,
with its SATA but Opteron's 250. I guess we could place SCSI adpaters on
the Tyan....
The other factor we're considering is that IBM will not certify its
Intellistation to be able to run SuSE 9.1, only RedHat. We do not use
RedHat.
Thanks again!
_____________________________
Ricardo R Palma
SYNOPSIS SA
Tel. (+51 1) 275-7523, 275-4708
email: rrpalma@synopsis.ws
www.synopsis.ws
"Richard Mixon (qwest)"
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Richard Mixon (qwest)
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rrpalma@synopsis.ws