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How to implement 4 raptors...bottlenecks?

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March 31, 2006 4:23:28 AM

Currently I have two WD 36gb Raptors running in RAID 0, at first I was happy with the new found speed of the RAID 0 but now I want MORE. How could I implement 4 (maybe more in the future) raptors and not be bottle necked by transfer rate limits. I was looking into pci express 4x and 1x cards as they are capable of supports higher mb/sec then pci slots but could only find 1 on newegg . I'm just not sure on how I would do this. Do you readers think 4 raptors would do more than 133mb/sec? Are there any pci 4x/1x raid controllers? My concern right now is bottlenecks, what would be the main bottlenecks? Thanks!




AMD 3500+
2x512mb Kingston HyperX (Dual Channel)
450 Watt Antec PSU
2 WD 360g Raptors (Raid 0)
ATI Radeon x700
Samsung SyncMaster 930b (19" viewable)
March 31, 2006 4:47:26 AM

try PCI Express Controller card products from adaptec, silicon image, maxtor

or google it.

4 disk can be created as raid 5 ( security+performance)

raptor150 are much faster than its 36 & 74gb version.

it was reviewed here in THG.
March 31, 2006 5:21:08 AM

yeah, a 4 port sata pci-e raid card or 4 onboard sata raid ports, with 4*36gb raptor hdds in a raid 0 array should have transfer rates in excess of 200MB/s (a generic non raided 7200RPM single drive gets from ~30-50MB/s)... definetly more throughput than the 2*36GB raptors i originally had... was literally astounded (with a fair amount of shock) at how quickly my system loaded things after purchasing the 2 additional raptors (windows xp did a complete install from the very beginning when setup started loading, to being able to go online in under 10 minutes)... considering you already have 2*36GB raptors, your limited to 36GB per drive in that same array anyhow... so youd get just under 150GBs storage also with them... the same capacity as the newest raptor, and all 4 of them raided will certainly be faster... and will cost you less only buying 2 more small raptors

edit: although... you want to make sure your PSU can supply enough power to all your hardware then, (and adequate cooling, because several hdds would typically be placed fairly close together) if you do decide to get 2 more... im sure it can, just a precaution to watch for
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March 31, 2006 10:08:16 PM

choirbass what raid controller are you using? Also how many watts your psu rated for, thanks.
March 31, 2006 10:26:18 PM

using the nforce4 onboard nvraid controller, and my psu is rated for 400watts... im not quite at total stability though, random crashes, dimming leds, problems booting up and shutting down... sometimes the raid array isnt detected... no problems since i started only using 1 raptor though... but, your 450watt psu might be enough

edit: its the same psu ive had for awhile though... when i was still using socket 462, ti4200, only 2 raptors... but since my system overhaul... it is REALLY not enough anymore, time for a new one lol
March 31, 2006 10:56:05 PM

From WD's site on 36GB Raptors:
"Transfer Rates
Buffer To Host (Serial ATA) 1.5 Gb/s (Max)
Buffer To Disk 72 MB/s (Sustained)"
http://www.wdc.com/en/products/Products.asp?DriveID=40

So in theory (heh), RAID 0'd should get you something like 144MB/s minus a little for the RAID overhead.

4 raptors, however, should be in the range of 288MB/s when RAID 0'd. I think the 150GB versions can hit 80MB/s per raptor give or take.

So yeah, you're stuck. PCI can't go over 133MB/s, unless its PCI 2.2 (533MB/s) or PCI-X(1066MB/s). Note that PCI-X is NOT PCI-Express.

If you have PCI-e (PCI-Express), then you can get a PCI-e RAID controller which will probably be sufficient for your idea. But that probably means changing your motherboard, since you only asked about PCI.

In any case, what you need to look for is the number of SATA channels that are on the RAID controller. Channels are NOT controllers and they are NOT ports. Typically you can find how many channels a controller has by doing a little research. Hopefully the manufacturer's website will tell you.

For example, silicon image's 3114 RAID chip.
http://www.siliconimage.com/products/product.aspx?id=28...
See how it clearly denotes that each of the 4 SATA 1 ports has the full 1.5Gbps per port? That means that chip has 4 SATA 1 channels.

Other chips may have a port multiplier. On page 2 here: http://seagate.com/docs/pdf/whitepaper/TP-539.pdf you can see the picture shows a port multiplier. This shares the bandwidth of the SATA 1 channel between 4 ports.
This isn't bad, as long as the bandwidth of your RAID 0 does not exceed the bandwidth across the port multiplier.
Example: Your 4 raptors can take 288MB/s, right? Clearly it would exceed the 150MB/s SATA 1 supports. However, if you had 2 raptors on 1 channel, and 2 raptors on another, you'd be fine because 2 raptors = 144MB/s and SATA 1 supports 150MB/s across those two ports where the raptors are connected.
March 31, 2006 10:58:30 PM

Sorry forgot to post this too:
From the WD site:

"Power Dissipation
Read/Write 8.40 Watts
Idle 7.90 Watts
Standby 1.76 Watts
Sleep 1.11 Watts"

Really, if an extra HDD overloads your PSU, you REALLY need to get a new bigger one!!! :) 
March 31, 2006 11:14:55 PM

well, the 7800GT by itself is recommended to have a 350watt psu... and 4 raptors, the X2 3800+ oc'd to 4600+ spec, and 7*80mm fans for cooling, that was just more loud than anything else lol... the psu is oddly louder now too after putting all that load on it, its leds were beginning to flicker and dim as well... seems as if its approaching failure... and im broke, so blah lol... ...and after i just said that, i looked through the side panel at the psu knowing it now has much less strain on it (only one raptor powered, 1*80mm fan running to cool the hdd, and the X2 is at stock speed again)... and the psu leds (and its noise level) are perfectly fine now, lol... oh well... guess its definetly time for a new psu then...
April 3, 2006 6:11:05 PM

That's true, but they implement this chip onto motherboards and other applications (as noted on the link I put there under Applications). I think some 939 boards have this chip but I can't remember which ones.
April 3, 2006 6:39:49 PM

Hope you're not running SLI or Crossfire. Otherwise there's gonna be a ton of traffic on your PCI-E bus that could slow things down. Remember that bus can get bottlenecked too.

I really doubt you'll see a difference that you can notice. I run 2 160GB SATA drives in RAID 0 and my loading times are like 3-5 seconds in Oblivion and when it loads the terrain I just barely notice a .5 second hop. So you already have more speed than me.
April 4, 2006 10:06:34 AM

Quote:
Hope you're not running SLI or Crossfire. Otherwise there's gonna be a ton of traffic on your PCI-E bus that could slow things down. Remember that bus can get bottlenecked too.


PCI Express devices don't share bandwidth the way PCI devices do.

Esp once you fact in that video cards have their own lanes :p 
April 4, 2006 1:24:46 PM

I have MSI's K8N Neo4 Platinum AMD64 mobo and currently I am using the built in NV RAID controller. The website says it has a maximum transfer rate of 300mb/s, is that buffer to disk or buffer to host? Maybe I could utilize the NV RAID for my unsure-to-be 4 raptor setup. I have my pci-express 4x and 1x slots open any raid controllers out there for those interfaces I looked around a little bit and didn't see any controllers that would work for me. Keep in mind I don't want a 500 dollar raid controller either 8) . If anyone has anyother prudent information on this subject please post it. Thanks a lot peeps!
April 4, 2006 6:21:38 PM

Quote:
That's true, but they implement this chip onto motherboards and other applications (as noted on the link I put there under Applications). I think some 939 boards have this chip but I can't remember which ones.

Doesn't make any difference.
Whoops, I stand corrected. wusy is correct because its integrated into the PCI bus if its onboard or as a separate PCI. :)  my bad.

@dan_the_man
I suspect the 300MB/s is refering to the SATA2 theoretical maximum bandwidth. That how much each channel of SATA2 can spit out. Its both from disk and to disk, if your disks can take it.
From what I read on these forums, NVRAID is supposed to be pretty good.
!