need advice on buying HD's for RAID set.

[xris24]

i am getting a nice tax return, and i want to setup a RAID set on my PC, for maximum performance, no fault tolerance. i havnt bought any of the hardware yet.

i have a soyo dragon 2 platinum edition mobo (sy-p4i875p)

it has 4 ide slots, so i can have 8 ide hd's.
i have 4 sata slots, so i can 4 SCSi drives.

(yes i can have 12 HD's if i want to, all at once)

my mobo has 3 on-board RAID controlers.

one is for ide 1 and 2, so i can have 4 ide drives RAIDed on that controller.

one is for SATA 1 and 2, the last is for SATA 3 and 4. so both of those can have two SCSI drives RAIDED on each.

got all that?

here is my question, what would be better for performance:

a RAID of four IDE drives...

-or-

a RAID of two SCSI drives...

i know one SCSI is better than one IDE for sure. but after that it gets complicated. can one SCSI drive out-perform two IDE's?

it gets even more complicated because they are RAIDed. how does RAID handle IDE cache? if the four IDE drives had 8mb cache, would i effectivly get 32 mb cache?

from what im told, SCSI drives dont even have cache, instead they have a built in instruction set, which handles how the drives looks for data, and it can alter its schedule to look for data it will need ahead of time, which minimizes how much the drive has to go back and forth.

assuming this is true, how is this handled in a RAID setup?

also, western digital has a really fast IDE drive 10,000 RPM i think. i believe it called the raptor? maybe? could using four of these for the IDE RAID make a big difference over SCSI? im not sure if i can afford these, but out of curiosity i'd like to know.

i have an 80 gig WD allready with 2 mb cache. i plan on using it just as a storage/backup drive to keep all my mp3's, compressed backups of games, etc...

the RAID is going to have my OS (has to be winXP for the RAID to function), maybe about 10 installed games, photoshop, and a few other things, but not much else.

as such i think the RAID needs to be only 20 gigs total.
so i'll probably get the cheapest (smallest) drives i can that still have the best performance (speed) available. i dont think anyone really makes drives in the 5 to 10 Gb range anymore, but i'll just get the smallest ones i can to cut down the price a little.

sOOOoOoOoOOOoOoO.....

do i buy IDE or SCSI drives?

what brands/models would you suggest? i am familer with IDE drives, but not so much with SCSI. can you tell ne what to look for in SCSI drives to know which is the best?

here are my current system specs, just incase it matters

fulltower atx case
350w power supply
soyo dragon 2 platinum edition mobo (sy-p4i875p)
Intel P4c 2.6 Ghz, 800 FSB, blah, blah, blah
1 GB of DDR 400 (not in dual channel mode, but will be soon)
GeForce 4 ti 4200 (4x agp) will upgrade when it breaks, lol.
80 gig hard drive, 2mb cache, 7200 rpm
cd burner, sony i think 40x maybe 52x, blehh...
NO floppy disk- who needs it?...weeeeeeee!!!!!!
sound card is onboard, but is nice enough - supports my...
5.1 dolby blahdidy blah blah surround sound blah speakers.
WIN2kpro (have to upgrade to XP for the RAID tho)
latest direct x and video drivers, etc...

a couple last questions.
1. my 350w power supply, will this need to upgraded also, to accomodate the extra drives?

2. is page file performance greatly improved by RAID (i assume some, but i wonder how much)

 

[xris24]

ummm...wait a sec...i have never used scsi drives before, do they connect to SATA slots or do they have a different type of slot all-together??

 

[sjonnie]

You can't use SCSI drives. You could use those Raptor drives from Western Digital though, they are 10,000 rpm SATA drives with near SCSI performance in everything except server benchmarks, but then I don't suppose you are running a server.

There's not point making a RAID array that will transfer faster than you 33b/33MHz PCI bus can handle, so two Raptors in RAID 0 will already max out the PCI bus so you wouldn't notice an improvement by adding more drives.

You could buy two 36GB WD360GB drives for $114 each or two 74GB WD740GD drives for $264 each depending on how big your tak return is.

<A HREF="http://www.anandtech.com/myanandtech.html?member=114979" target="_new">My PCs</A>

 

[xris24]

hmm..i didnt realize that the raptors were that cheap, they may be my best option. i looked through my mobo manual, and found this:
silicon image sil3112 sata raid chip- this is one of the raid controlers. it says it features 32bit 33/66mhz pci interface.

i can still only put two devices on it, but does that change anything?

also, i have a setting in my BIOS for selecting boot orders, looking this up in the manual i see that scsi is an option, but as a pci scsi controler...

im guessing here (im self-taught) that5 you can get a pci scsi card, similer to pci IDE cards i have seen, and i could have the pc boot from them with this option. (just trying to learn more about scsi.

would two raptors be faster then four reguler ide drives?

im thinking four IDE's might edge out the two raptors, but i dont know as much about bus and all..

 

[grafixmonkey]

Sounds like fun. Just promise me you won't get a raid card from Promise. You'll have all kinds of problems if you do.

The two raptors should be able to outperform four normal drives. Their transfer rates might be close, but the raptors spin so much faster that random reads and writes (i.e. disk caches, swap file etc.) will be faster because the drives' seek times will be lower. The Raptors should also be a lot more reliable, because they come with a really long warranty. They are, however, much much more expensive per gigabyte.

Most PCI busses run at 33mhz, but this is changing with new PCI standards. If your Raid controller is indeed running on a 66mhz pci bus, then that doubles your PCI bandwidth and you should be able to get lots of speed out of a Raid-0.

In the BIOS, the boot option that says "SCSI" also applies to IDE raid. I don't know why this is, probably for simplicity, but as far as windows in concerned and as far as Bios is concerned, an IDE raid controller is considered a SCSI device.

About IDE Raid vs SCSI Raid. I tend to believe that SCSI is where corporations look when they want a RAID solution, and SCSI has traditionally been the place where RAID has always happened. I think the IDE raid solutions are the result of someone realizing that normal consumers would also buy raid solutions, and expanding / converting the long-existing SCSI raid market into the IDE sector as well. So, the point is, I think the SCSI raid cards are probably a lot more mature and feature-rich than the IDE cards, mainly because of their intended market. A corporation, for example, would not have put up with the problems I've had from Promise cards, and may very well have sued over them, because their cards just plain don't work right. I've had all kinds of data loss that can be traced directly, and only, to the Promise Raid card. But, that's just my educated speculation about what you would find in the SCSI raid market.

That said about SCSI raid, I've heard nothing but good things about HighPoint Raid-0 cards, and many people have told me that 3Ware is the best for IDE raid cards in general.

 

[arkus]

I've just modified my system and am currently using:

4*WD 36gb Raptors in Raid 1/0 on a Highpoint 1640 PCI RAID card

2* 120gb WD Caviars on the mobo (Abit IS7-G)

Seems nice so far (been running for a few days). The RAID 1/0 may be over the top for your purposes, i don't know, but it allows me to run at RAID 0 speeds with piece of mind. However, apparently the 72gb Raptors make use of newer tech and are comparitavily faster than the 36gb, so if you want outright speed, maybe go down that route.

 

[xris24]

great info you two!

i think for the upgrade i will probably end up going with the 2 raptors in raid 0. i think i would *like* to have a scsi RAID setup, it seems like something i would do, but i dont want to go off trying to buy hardware i dont know much about, or worse, trying to configure it.

i know i can setup the raptors without having any problems i can handle. maybe i can find a scsi guru in my neighborhood i can leech knowledge from...

thinking about all this has brought up one more question in my mind. how is a RAID 0 with two drives different from a stripe set?

ive used stripe sets before, and it was pretty neat. the first pc i used was built by a freind. it was a 433 celeron wit 256 mb ram. not bad for a pc built from scrap (litterally). we only had like three drives to use, and they were all between 1-4 gigs, and really old and slow! thats why we used the stripe set, to help the bottlenecking a little.

the only difference i can think of at the moment (if im right at all) is that with a stripe you have to have the os first to even set it up, and i dont think you can even put an OS onto a stripe set for some reason. this true?

that would be reason enough to go with RAID 0 alone, but are there any other advantages? how about swap file, can it go on a stripe set? i also remember that in a stripe set the drives didnt have to be the same size or speed, but the set would be based on the slowest drive, and had to be a multiple in size of the smallest drive. with RAID you basicly have to have the same size/speed right, preferably the exact brand and model?

im going to build a pc for a friend/co-worker sometime this week, and i just want to clear up a few grey area before i go spending someone elses money. he wants to spend a grand, so i want to make it something that really performs and will last him a good long time. plus, with it being the same as mine, i have to be able to explain why its worth it for it to be a little more complicated.

p.s. building his pc is going to be fun, im going to make him actually put it together, ill just tell him what to do etc... it'l be good for him to understand a little more about his pc. plus im going to make him do all the installs etc...while i sit back and watch heheh ;p.

however, it being a near clone of my pc, which i build about 6 months ago, im going to get karma payback, as i see him getting much lower prices than i did on the same components...anyone have a fix for thumping veins in the forehead?

 

[arkus]

RAID 0 uses striping, that's what makes it faster. And yes, you can install the OS onto a RAID array that uses striping (I have WinXP on my RAID 1/0 array on the 4* Raptors). Some people may recommend against having the OS on a RAID array, and it can cause a bunch of problems, but it's up to you.

I think maybe have another look at the RAID FAQ, or perhaps look here <A HREF="http://www.storagereview.com/guide2000/ref/hdd/perf/raid/levels/singleLevel0.html" target="_new">http://www.storagereview.com/guide2000/ref/hdd/perf/raid/levels/singleLevel0.html</A> for a great RAID FAQ that should answer all your questions.