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What would be the best RAID setup for these drives and appli

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August 21, 2006 4:55:02 PM

I have 6 18gig Fujitsu U320 MAS3184NC drives I want to RAID with a dual channel Adaptec U320 - 2200/s controller w/64MB Cache. I want to keep at least one out for a spare. I also have U160 ST318452LW (3.6ms seek time), ST318406LW (5.2ms seek time) drives that I can use for this project. First priority is speed second priority is security. This is the project.


Old system
P4 @ 2.8Ghz,
1 Gig Ram,
SATA HDD 80gig,
Quadro 900xgl AGP Video 2 port card +
Quadro NVS 400 PCI 4 port video card


NEW SYSTEM
Core 2 Duo E6600
2 GIG’s Ram
PCI-X based SCSI’s RAIDed
2) Quadro NVS 285 PCI-Express Video Cards
1) Matrox PCI-X video card


I have 6 monitors displaying financial data I need to change all 6 monitors at the same time to display other data the old system took 45 seconds to do so. I really need it to be less than 5 seconds. I am changing to a workstation MB with 2 PCI-Express slots and 2 PCI-X slots. This will eliminate the bottlenecks and give me the increased bandwidth I need. These charts are 2D ONLY in changing to PCI-Express there has been a dramatic improvement in the video portion now I need to optimize the Disk I/O. This is the only task this computer is going to be doing. Going RAID at this level may be overkill I just don’t know.

I have read a number of article on RAID and understand the different types but with these drives being so fast I am a little puzzled on what to do. These drives have a sustained throughput of 114 MB/s each burst is 320 MB/s. Therefore it seems that 3 drives will saturate the channel but I do not know if there is enough data to even worry about the sustained rate of transfer. How long does the burst rate of transfer last? Is there an immediate drop off or a taper to the sustained rate. How long does that take?

Since I have dual channel that also presents more options. Are there any scenarios where I should use both channels, or where it is best only to use one channel?

Remember I have 6 Fujitsu drives and 2 Seagates all 18gigs each ( I could also have a pair of the U160 ST318452LW if needed.

Senarios I can think of – Need opinions on these or others you can think of.
1) use 1 channel for OS and another channel for the application (stripe or stripe and mirror)
2) use both channels for stripe and mirror
(a. stripe on one channel w/mirror on the other)
(b. each channel contain a stripe drive and each channel contain a mirror drive)
3) use one channel for stripe w/parity RAID
(a. 3 stripe & 1 parity, or 4 stripe & 1 parity with OS on another channel
as above but with the OS included in the stripe and parity RAID

Thanks in advance for your Help
August 22, 2006 6:10:11 PM

Quote:
I see you're going with the Asus P5WDG2-WS Pro as well.

It sure has been a while since one would find RAID 1+0 useful which in your case is the perfect solution.
RAID5 is out of the question (don't ask me to explain why as it'll take ages to explain).

-Take six of the MAS3184NC and put them in RAID 1+0, half-half on each channel (use that for OS and application)
-Buy a used U160 RAID card and give the ST318452LW (X15-36LP) and ST318406LW (36ES) to the old P4 rig.


Raid 1+0 is a great option here. And you do want to keep those U160s away from the new setup. Are the spin times the Fujitsu's the same as the Seagates? I sleep better a night ( if it was me) to only pair like drives for your new system. Then I would get a cheap 320 single channel card and put it in your old system.
August 27, 2006 2:08:08 AM

What is the difference if I put the raided drives on one channel and a seperate OS drive on another channel. The throughput range is from 90MB/s to 115MB/s on the drives the only thing I can think of is that the channel may hit the 320MB/s limit. But I wonder if there is that much data for that to be a problem.

I have received my Conroe E6400 and have 2 gigs of ram for the board whenever I can get it through Compusa via Ingram-Micro.
Related resources
August 27, 2006 3:19:37 AM

BTW, Ingram-Micro is one of the WORST suppliers ever, you could probably get it cheaper through Newegg :)  Go with Tech-Data if they can.
August 27, 2006 4:31:43 AM

I have a credit at CompUsa so I am sort of at their mercy. Good news I am getting it through the business sales dept. theyhave better pricing. Tech Data does not have it on their list of upcoming inventory, Ingram does.

BTW ever heard of MA Labs? they have some pretty good pricing.
August 27, 2006 7:45:01 AM

I just checked my Tech Data account, looks like it's there at $309 (non pro), to dealers like myself, gotta assume CompUSA will have a markup, so compared to newegg's $330, I'd just go newegg. I used to use MA Labs and Tech Data almost exclusively when I had my store. Then Newegg came around and between their quick and free shipping (at the time almost everything shipped free) they became my primary supplier for almost everything. Plus they'd give me discounts if I ordered a bunch or hard drives, optical drives, etc. I haven't had an Ingram account since the early 90's.
August 27, 2006 10:30:58 AM

I have to wonder if you're going about this all wrong, if you NEED to have ample memory to cache more, rather than low-latency SCSI. I think it's conceivable that you need exactly zero SCSI drives, that one server board with enough memory and a single 400GB SATA drive would work. Besides that, if you're constantly thrashing those drives they may not end up so reliable.
August 27, 2006 7:07:27 PM

Quote:
I have to wonder if you're going about this all wrong, if you NEED to have ample memory to cache more, rather than low-latency SCSI. I think it's conceivable that you need exactly zero SCSI drives, that one server board with enough memory and a single 400GB SATA drive would work. Besides that, if you're constantly thrashing those drives they may not end up so reliable.


That's exactly what SCSI drives are built for. I've used those model Seagates in a bunch of servers, terminal, sql, exchange, NEVER had one die. It think if he has the parts it won't hurt performance to do it :) 
August 27, 2006 9:16:51 PM

Quote:
Besides that, if you're constantly thrashing those drives they may not end up so reliable.


I have to agree with Michaelahess on that one for sure. These are enterprise drives, commercial hardware not consumer stuff. The reliability factor through constant use is built in. I do know some guys that have had to replace some ide drives about every 6 monthe because of the "thrashing". Also it is not like I am going to be using them in that fashion anyway. It is just when I change I need that change to be quick. The controller has 64MB cache so that will be a great boost added to the 8MB cache on each drive.

It looks like Newegg finally has the board I was looking for available also.
!