Sign in with
Sign up | Sign in
Your question

which HDD's for RAID-0 (many channels)

Last response: in Storage
Share
March 22, 2004 6:55:26 AM

Here's a challenging problem for you guys...

I'm building a RAID-0 array with lots of channels. I'm trying to figure out which hard drives would perform fastest in it, since I've seen a great deal of variance in hard drive performance from manufacturer to manufacturer.

Just so everyone knows, this system will be built for throughput - 3Ware PCI-X raid card, dual xeons, and all - so more hard drives will not be maxing out any busses.

My initial reaction was Seagate 80GB drives, since they are very cheap for their size, and I could put six of them in the array to start with. I then looked at the 36GB Raptors, and according to benchmarks at storagereview.com they will transfer at about 1.8x the speed of the Seagate drives, cost about twice as much, and are theoretically more reliable (good thing to have in RAID-0) so I'm considering them too, but neither of those options are very good, here's why:

The seagate drives have a 1yr warranty, I'm afraid they might take to failing on me like my Maxtor drives have been for some reason. Given 6 of them in the array, that's a high risk. They also transfer very slowly for any kind of hard drive, I would prefer a better low-cost PATA option.

The Raptors are great... but they're SATA. A SATA 3Ware Escalade 8506-12 costs $700 or more, while a PATA 7506-12 costs $550. I could buy three more 80gig Seagates for that money. I also don't know how I would go about getting the system to work if I had some SATA and some PATA drives (I already have three 200gig drives for a RAID-5 array, a large investment that I don't want to trash.) I'm using hot-swap enclosures, and can't put a SATA->PATA converter on the drive itself (and put it in a PATA enclosure), it wouldn't fit inside the tray. I could put the Raptors inside a SATA enclosure and put SATA->PATA converters on the back of the enclosure. In fact, SATA enclosures are easier to come by than PATA enclosures. But then how would I put my existing 200gig PATA drives into an enclosure?

I need to use 5-in-3 enclosures like <A HREF="http://www.orbitmicro.com/products/accessories/removabl... hdd trays/BRIDE35.htm" target="_new">This One</A> to house my drives or I cannot fit my RAID card's maximum drive capacity into the case. (planning for the future.) A "universal" enclosure supporting both PATA and SATA at once would pretty much solve the problem, but where to find one?

The last problem is, I'm a bit wary of these converters. Should I be using devices that convert between PATA and SATA, in a high speed RAID configuration?

So if anyone knows of fast 20, 40, 60, or 80 gig drives that would help a lot. A good way of combining SATA and PATA drives on the same RAID card would be even better. The seagate was benchmarked at 43MB/sec max, 25MB/sec min, which is pretty slow, low density I guess, so I'm really hoping for some better options than I've been able to find.

More about : hdd raid channels

March 22, 2004 12:28:46 PM

How much are you willing to spend? The best option would definatly be the Raptors with the SATA raid card, but thats gonna cost you shed loads. But do bear in mind the raptors come with a 3year warrenty and are probably much more durable than the seagate drives.

Its really a toss up between price and performance, what do you plan to use this system for out of interest?

[Insert witty comment here]
March 22, 2004 6:03:12 PM

The system will be used for video compositing, 3D rendering, and audio production. Because I plan on doing audio on it, it would be nice to keep the noise down, but I will have a separate gaming rig with near-zero noise and a better sound card so it's not an essential factor. Soon I will be compositing a decent amount of raw, HDTV resolution video, so a large and fast RAID-0 is essential.

The total system cost is now at $2600 or so. To get the PATA raid system and six Seagate drives makes up $1350 of that cost, broken down like this:
$560: 3Ware Escalade 7506-12
$200 ea.: 5-in-3 PATA raid cages X 2
$66 ea.: 80GB PATA Seagate drives X 6

I want to get the Raptors, I think they would be far superior. They would also not change the cost of the drives much, if I get the 36GB raptors (the old versions). The only problem is that using Raptors forces me to get a SATA raid card, which costs $700 instead of $560, and makes me get PATA->SATA converters for another $90.

So the answer is, I'm already spending a lot, and I am willing to spend a lot, but I'm still trying to keep the price down if possible. I should probably move to SATA anyway.

I'm going to go shop for RAID cages again, and see if SATA cages are cheaper... They're certainly more numerous.
Related resources
March 22, 2004 8:18:14 PM

Is it posible to get a ata2sata adapter.. ? if so could u point me in a direction to where i can view one.. and maybe buy one ? ..

oh btw .. if u want speed do not put more than 2 HDD in a raid 0 config preformance do not dubble after that ( ie if u have 4 hdd in a RAID 0 config u will not get 4xnormal HDD speed but maybe only 2.5xnormal speed

.. try and see if u can finde a raid controler that supports RAID 7
its a nonstandard but its the fastes while its secure too link -->
http://www.acnc.com/04_01_07.html
and
http://www.pcguide.com/ref/hdd/perf/raid/levels/singleL...

there u whould be able to mount all ur disks in one raid confing and it needs around five disks to run.
another thing .. to improve speed u should buy another RAID controler deviding the HDD's over 2 controler helps alot there too..
and final .. if u have money buy SCSI.. due to the preformance of a ATA HDD is strictly peek values.

i dont know if this helps .. i my self have been running with a 2xraid 0 config with 4 HDD
2 IBM's
2 Maxtors
on a promise Fasttrak 4000 sx
March 22, 2004 8:55:50 PM

Quote:
oh btw .. if u want speed do not put more than 2 HDD in a raid 0 config preformance do not dubble after that ( ie if u have 4 hdd in a RAID 0 config u will not get 4xnormal HDD speed but maybe only 2.5xnormal speed

That's because you only have a normal PCI slot. The throughput of the 32-bit PCI bus is only 132MB/s or so. The throughput of the 64-bit 66mhz PCI-X bus is 528MB/s.

RAID-7 sounds interesting. Have you ever seen a controller that supports it? I haven't. I know that none of the 3Ware controllers support it.

AMS Electronics makes a PATA->SATA adapter. Its model number is the DK-154SS or the DK-130SA (two diff. kinds, different shapes/sizes) <A HREF="http://www.amselectronics.com/Products/Comet/DK-SATA.ht..." target="_new">here's a link.</A> There's also a StorCase RAID cage <A HREF="http://www.storcase.com/dataexpress/de400.asp" target="_new">Here</A> that connects to SATA and can support either a SATA or a PATA drive tray, but I have no idea how you go about obtaining the replacement drive trays, and getting that drive cage would reduce the total drive capacity of my case by 2 drives so I'm still debating it for my own rig. It claims it will automatically recognize the connection of either kind of drive tray, and it sounds like it automatically converts it if it's a PATA signal. I only see SATA ports on the back in their rotating 3D view applet, but it doesn't let you look very closely, and there's something resembling a PATA port on one side but I can't tell what it is.
March 22, 2004 9:00:48 PM

Save a bunch by not buying a 3ware card. If you are just going to run RAID-0 use the 8-channel RocketRaid 1820 from Highpoint, $165. Also the Highpoint card will outperform the 3ware card in RAID-0. Then you can buy 8 36GB SATAs.

<A HREF="http://www.anandtech.com/myanandtech.html?member=114979" target="_new">My PCs</A> :cool:
March 22, 2004 9:18:37 PM

Duh, should read to the end of the thread. You want to run RAID5 and RAID0? Then you should definitely run two cards (or did we have this discussion already and you said you didn't want 2 cards). What MOBO do you have? I'd recomend you get a multiple PCI-bus board i.e. Intel SE7505VB2. But at the very least it should have at least one PCI-X slot and another 64/66 PCI slot.

3ware 7506-4 $245
Highpoint 1820 $165
5-in-3 SATA enclosure $170 x2
WD360GD $109.50 x6

Total cost $1407 + shipping. You could probably get cheaper enclosures, although I remember you wanted cool looking ones.

<A HREF="http://www.anandtech.com/myanandtech.html?member=114979" target="_new">My PCs</A> :cool:
March 23, 2004 12:47:15 AM

Current systems plans:

MOBO, Choosing between the following:
<A HREF="http://www.tyan.com/products/html/thunderi7505.html" target="_new">Tyan S2665</A> ($379)
<A HREF="http://www.supermicro.com/products/motherboard/Xeon/E75..." target="_new">Super X5DAE</A> ($453, because of buying ECC RAM, board is $353 itself)
<A HREF="http://usa.asus.com/products/server/srv-mb/pp-dlw/overv..." target="_new">Asus PP-DLW</A> ($289)

I was going to get a 12-port 3Ware and run one RAID-5(3drive) and one RAID-0(?drive), leaving the raid-5 with only three and buying as many raid-0 drives as made sense. That was when I was looking at PATA. But now, I don't trust the stability of PATA drives for raid-0 (I've had two failures on the raid-5 already) so I'm getting the old 36GB Raptors for raid-0 instead. That brings in a whole host of problems.

First, I just found this enclosure system:
<A HREF="http://www.aicipc.com/index.cfm?fuseaction=wwwroot.acc&..." target="_new">3-in-2 size</A>
<A HREF="http://www.aicipc.com/index.cfm?fuseaction=wwwroot.acc&..." target="_new">5-in-3 size</A>
Plus <A HREF="http://www.aicipc.com/index.cfm?fuseaction=wwwroot.acc&..." target="_new">These Things</A> which convert PATA to SATA inside the drive tray itself, and connect to the same SATA backplane. This would allow me to keep my three or four 200GB PATA drives and use them in the same enclosures as the rest, and just throw out the converting trays whenever my system becomes completely SATA.


As far as which RAID card(s) to get... Is it the bus bandwidth of PCI-X that makes you say to get two cards instead of one? Or is it the price? The reason I ask is, my nForce2 motherboard did not like having two Promise RAID adapters in it at all... If you say this won't be a problem with the 3Ware and Highpoint, I'll consider the problem solved. I would have thought having both arrays on the same card would be better than having them separate though? Less system resource use? Will my raid-0 array max out the PCI-X bandwidth and leave none for the raid-5, is that why? (I can see that happening with six raptors... I admit those prices you posted look very tempting.)

My motherboard, btw, will be very low on slots. The slot adjacent to the AGP slot will be obstructed by the graphics card heatsink. All three of the boards I was considering have (for my purposes) one dedicated PCI-X, two shared PCI-X, and one 32-bit PCI which will have a sound card. If I get two RAID cards, then there will be no way to add a second 32-bit PCI card to the system without locking one RAID card to 33mhz. (which wouldn't be a big deal, for the Raid-5, because it can't transfer very fast anyway.)

One last thing: When I shopped for ECC memory, I found PC-3200 DDR ECC memory and used that price. Would this be just as fast as any other memory I could buy for the Supermicro board? If using PC3200 ECC memory will not be slower than using non-ECC memory, I will get the Supermicro board. (it has more headers for pretty lights on the front panel!)
March 23, 2004 5:52:07 AM

Let me explain what I was thinking. If you have both RAID ararys on one card the card can only access one array at a time. That will mean both arrays are tied up when one is being used, although that's clearly not an issue if you only have one PCI-bus. If you put each array on a separate card on a separate PCI-bus then you get no access issues. The PCI bus mastering will handle everything and system resources are not going to be limiting on the system you are building. Either the Tyan or the Supermicro board will be fine, they both have two independent PCI busses which should give you great access to your RAID arrays - especially if you have them on separate busses. On the Tyan and Supermicro boards the PCI-X slots are at the bottom so your AGP card will sacrifice an 32/33 slot. Highpoint and 3ware cards will work together no problem. It's just the promise drivers that can't handle multiple cards.

Yeah, they were the enclosures I saw on servercase.com. Should sort you out nicely.

As far as memory goes there is no need to get more than DDR266. The E7505 chipset will not support 800MHz FSB. On the other hand Nocona - the 800MHz version of the Xeon - is supposed to be released next Quater along with the Lindenhurst chipset which will support DDR400. It'll be expensive of course, but you can expect prices of the older stuff to drop.

<A HREF="http://www.anandtech.com/myanandtech.html?member=114979" target="_new">My PCs</A> :cool:
March 23, 2004 12:39:43 PM

----------------------------------------------------------------------------------------------------------------------------------------
That's because you only have a normal PCI slot. The throughput of the 32-bit PCI bus is only 132MB/s or so. The throughput of the 64-bit 66mhz PCI-X bus is 528MB/s.
----------------------------------------------------------------------------------------------------------------------------------------



what I was told is, that it isnt the PCI bus that limits my raid .. I only have like 30 - 40 MB/s continued read and write ( that is thested with a little progrma that creates a file and mesure the time it takes to do that )

and I tryed to set all 4 HDD's in one RAID 0 and I still only got like 40 MB/s ( creating a 300MB file ). not even close to thoes 132MB/s

but what I was told, is that the speed given by manufactores on ATA drives is purly peek preformance ..

( so a ATA 133 drive will most surely only deliver 133 MB/s in a short instance and after that fall in preformance)

that is why most pro server configs use SCSI.
( I was allso told that if you see a ATA 133 as a ATA 133Mbit/s you'll get a more accurat speed :)  )


---------------------------------------------------------------------------------------------------------------------------------------
RAID-7 sounds interesting. Have you ever seen a controller that supports it? I haven't. I know that none of the 3Ware controllers support it.
--------------------------------------------------------------------------------------------------------------------------------------

the only company I've seen, that supports that RAID config is advertised at the link I posted. dont know if there is others that support it. but im still looking after it.

btw what is PATA .. never heard that expression before

and btw i thought a PCI-x was full duplex ie you get 500MB/s in each dir = 1GB/s total
March 23, 2004 6:28:56 PM

ok... hmmm... There are some misconceptions to clear up.

ATA133 is the BUS speed, not the speed you can read/write from the disk. Manufacturers really don't give the actual disk speed, except as a disk RPM, and the actual speed depends on the disk RPM, data density, and position of the data on the disk. Real performance also depends on the seek time. No single ATA or SATA drive in existence can fill an ATA133 channel by itself.

I had performance greater than either of the configurations you reported (2-drive or 4-drive), using three 60-gig maxtor drives in a raid-0. What card were you using for it? How did you measure the performance? If you used SiSoft Sandra, you have to look at the full report, because the number it gives you is an average of sequential read/write and
random read/write performances, all combined into one average number.

Most pro server configs use SCSI because:
* the SCSI bus has a humongous bandwidth, and an entire RAID subsystem can connect through a single SCSI cable to the server/workstation and not lose performance. Also, multi-drive enclosures can connect through a single bus, can be chained together, etc. so SCSI is a much better bus for having many, many drives.
* SCSI drives are much more reliable, making extremely large Raid-0 systems feasible.
* SCSI drives are available in 15,000rpm so you can have a much faster SCSI RAID system than you can an IDE RAID system, using the same number of drives.
* Businesses don't give a crap how much their equipment costs. Equipment cost is negligible compared to cost of hiring employees, so a more expensive, more reliable server costs much LESS because they don't have to hire someone to maintain it.

PATA refers to Parallel ATA, as opposed to Serial ATA. It's pretty new, but it's common terminology nowadays because now you have to distinguish between it and the new SATA standard.

There's no point whatsoever in adding upstream and downstream performance to get a higher number. If you write to an infinitely fast Raid-0 system using PCI-X, it will write at 500MB/s. If you read from it, it will read at 500MB/s. If you read a file from an infinitely fast RAID-0 system, process it, and write it back to the infinitely fast system, that process will happen at 500MB/s. If you read from one inf. fast RAID, process, and write to a different inf. fast RAID, that will also happen at 500MB/s. Saying it can transfer 1GB/sec just confuses things.


If your system wasn't limited by your PCI bus, then there must have been something else limiting it. Was the processor in your system fast? Were you copying a file from a single drive onto your RAID system? Were you copying a file from a ramdisk onto your RAID? From the RAID, to the RAID? Were you using a benchmark program? Was your RAID system defragmented?

If you were copying from a single drive to your RAID, that would cause your results because a typical single PATA hard drive transfers around the 40MB/s mark. If you used a ramdisk, then that's not the case, you should have been able to copy it full speed. If you were copying from the RAID to the RAID, you were measuring random read and random write performance more than sequential r/w performance. Same if your RAID system was fragmented. If the processor in your system was slow, then that might also cause your RAID performance to be poor. If you were using a benchmark program, you may have gotten a combined "score" and not an actual performance result (SiSoft Sandra does this unless you look closer), because it's really impossible to measure any drive's performance, especially a RAID system, down to a single number. There are too many circumstances, too many if's and then's, and too many variables that make a difference. You may even have used a very small stripe block size, and you were simply pushing as many block-stitches per second through your raid card's chips as it could possibly handle.
March 23, 2004 6:52:00 PM

in response to sjonnie -

So, the card being able to access only one array at a time means, that you have a total of some maximum throughput to the raid card that must now be shared between two arrays, rather than two "maximum throughput" busses, each having a single RAID array to itself? Or must the card "ignore" one array entirely while it reads/writes the other, as opposed to having two controllers that can read/write in parallel?

Will the Highpoint card outperform the much more expensive 3Ware card in Raid-0, even when there are six Raptors on it? Seems people tend to test those cards with a small number of drives, and I've grown a certain irrational mistrust of cheaper products because of Promise... The 3Ware card I would get would be the 9500S-12 or 9500S-8 (with Raptors, 5 raptor raid-0 and 3-PATA raid-5 would be quite enough really.)


<P ID="edit"><FONT SIZE=-1><EM>Edited by grafixmonkey on 03/23/04 03:02 PM.</EM></FONT></P>
March 24, 2004 5:47:55 PM

I dont beleve in test program like sisoft and PCmark2003, or others due to that in sisoft i get like 300 MB/s sequential write and read ( just to take an example ), and i tryed to compress my drive and test it with pcmark 2003 and got a 600% incress in preformance. so the only program i use is a tiny little program, where you have two choices either create a file at a surtain size or copy a file from one location to another, mesures the time it takes in seconds.
so if i copy a file from one RAID 0 config to another RAID 0 config and it tells me that it does that with 30 MB/s ( 10 sec).after a info like that i have a hard time beleving in a program that tells me that i have 300 MB/s write capability.

my system :
-Athlon XP 1900+ (1600Mhz, 266Mhz)
-1 GB 333 MHz RAM ( running Async)
-radeon 9800 pro 128
-Promise fasttrak SX4000 (ATA133 controler with 4 Master controlers (no slave)) with 256 SD 133 MHz RAM onboard
-1st RAID config : 2x IBM GXP120 80 GB 7200 RPM's ATA133
-2nd RAID config : 2x Maxtor Fluid 80 GB 7200 RPM's ATA133
-Sound blaster audigy 2 ZS
-Plexwrite 48x
-Pioneer DVD

the PCI slots is filled so there shouldnt be any shareing between them, and the strip block size i use is 64KB the biggest available. and my RAID controler is set so it copies the files to its internal mem before writeing it down on the HDD ( a bit unsafe but fastes setting ).
beside my processor's speed i cant see what should course it to run slowly.


in regard to the other things
- the SCSI what you wrote was roughly what i was told too :) 
- the PATA question was kinda a dumb question :)  i could have told my self that .. hehe.
- bout the ATA133, didnt know thx for clearing that up :) 


ps. sry for my bad english :p 


Btw i work at ISP if you can call it that ( not doing anything importan just a student job for a little extra cash) and ive been talking with them about what HDD to buy if it shouldnt be SCSI ( mainly due to that i was thinking of changing my self, though enden up in me buying Maxtor fluid ), and most of them said Seagate. u get most preformance for the money.
ive used IBM HDD's the most of my life and im moving away from them, so if it was up to me dont buy IBM.
March 24, 2004 9:39:36 PM

No worries, I had quite a bit to learn about raid not just two months ago.

Are you sure Windows isn't first reading that file to memory, and then copying the file to the second disk? Are you sure that both the reading and the writing take 10 seconds each? Because I would assume that you spent 5 seconds reading the file, and 5 seconds writing it, for a performance of 60MB/sec on each disk, not bad for a raid-0. I would also assume that Windows spent at least some time "preparing to copy" the file. (try copying your Temporary Internet Files folder from one drive to the other, you'll see what I mean.) It may have also run the file through an antivirus program before actually allowing the copy. The controller might also be incapable of simultaneously accessing two different arrays, I've had people tell me this before. You were also testing only a single point on the disk. Disks read faster at the beginning than at the end. If you had filled the drive up, then that area of the disk you tested was probably the slowest, whereas SiSoft would have averaged the performance of the entire disk and given a higher number.

Benchmark programs are designed to eliminate all those factors from the currently installed OS and software configuration. They're good for comparing speeds of two different components, but they are terrible for predicting how fast a whole system will run when put together. For example, a benchmark might tell you that a 3-disk raid-0 is faster than a 2-disk raid-0, or that a raid-0 with raptors is faster than one with seagates, but it will NOT tell you that if you assemble this RAID on your motherboard, install the NTFS filesystem, and use Windows XP to copy a file to another drive, that you should expect to get the same transfer rate the benchmark gave.

I would guess if you tested average sequential read performance over the whole disk of a single drive JBOD you'd get 40MB/sec or so, with a 2-drive raid-0 80, with three drives 110, and with four drives 120. This is because the PCI bus would max out at 132MB/sec, and some of that would be protocol overhead. I'd also guess that if you copied from one four-drive raid-0 to another four-drive raid-0 using your "copy file and measure time" method, you would have estimated the transfer rate to be about 60MB/sec.

(disclaimer: those are just guesstimates for the purpose of argument - don't go pointing me to StorageReview.com and saying I was 20% off or anything)
March 25, 2004 7:01:02 PM

No No i will not do that :) 

do you use RAID atm. cos it could be fun if i could get you to test your HDD with that program for a little compair ..

http://www.majorgeeks.com/download1340.html

no amount of words can explain a first hand view and feal of a program. and you might figure out how it works in basic, better than relying on me trying to explain it :) 
March 25, 2004 7:19:50 PM

My old raid-0 is down, I could not make the tx2000 run at the same time as the sx4000 so I had to choose raid-5 only. Once my new computer is put together, soon, I will try your test though. It will have a system that will not compare very well though, an 8-port HighPoint raid-0 controller connected to 133MHZ PCI-X, and a 4-port 3Ware Raid-5 controller connected to separate 66MHZ PCI-X bus, and the raid-0 will be composed of four Raptor drives.

Which RAID card were you using in your setup? Was it built in to the motherboard?
March 26, 2004 10:07:49 PM

the first one i used was a Adaptec 1200A then i switched to a Fasttrak SX4000 from promise and its not built in.

btw nice setting with the RAID .. wish i had that kind of money :) 

well if you will u could run it on the drive ur useing now it should roughtly be half the speed of mine.
March 27, 2004 1:32:11 AM

The drive I'm running now is a Raid-5 array that's running in critical mode due to a failure of one of the three maxtors... I don't think it would be a very good comparison to any other system, even another raid-5, much less a functional raid-0.

I will probably end up having a raid-0 array between two 60gig 7200rpm PATA maxtors, in my gaming system (just turns out I had the parts lying around) so I'd be willing to try it on that. I don't think that my new workstation raid-0 would compare very well either, though I'll post the speed it gets. It's not very fair to compare two 7200rpm IDE drives on a 32-bit 33mhz PCI bus, to four 10,000rpm Raptors on a 64-bit 133mhz PCI-X bus. But I'll be interested to see what your program reports the speed is.
!