SlackerXL

Tips about a poor-performing scsi raid 0

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Greetings everybody.

I recently bought the following scsi config for €350

- 2x73gb Maxtor Atlas IV 10krpm u320

- dell Perc3/dc (lsi megaraid 1600) scsi u160 raid controller with intel i960 processor and 128 mb cache ram

- and an old & huge perc4 controller for free with the whole package...

i intended to replace my aging 2x36gb raptors raid0 setup

and hoped that the Maxtor's could justify the cost....

and thats why i decided to go with the new P5WDG2-WS which features a pci-x slot

for the perc3/dc card

As the motherboard isn't yet available

and i've already received the scsi parts,

i decided to give it a try on a normal pci slot just to see if everything is working ok

the results in winxp were dissapointing

27mb/s burst and 50 average at first

after a lot of inet search i changed some settings in the raid bios and got up to

55-60mb/s burst and 58 average

but still i think its very poor compared to my sata 2x36gb raptors raid... 100mb/s

any ideas?

any tips or tricks?

should expect to see any great difference once i install it on the pci-x slot?

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forgot to clarify the fact that i'm not interested in data integrity at all

all i want is to get the max performance for my OS and apps (photoshop, cad, games)

as i already have a rocketraid 1640 4x200gb baracuda sata raid 10

for my data

so any advice should be oriented towards that direction

(please excuse my English

and let me know if some of the above mentioned don't make sense :) )

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Could somebody at least post a link to some info regarding my problem?

i've done some general searching but nothing relevant came up

(at least for WINxp & Raid 0 on this particular controller)

thanx in advance

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i thought that pci would be lmiting the total bandwidth if it exceeded the 120mb/s limit

but in my case the scsi raid 0 couldn't even match the performance of a single SATA drive...

(remember we are talking about 10krpm 73gb Atlas IV, somewhat similar to a 73gb raptor performance-wise)

is there really a chance that the pci-x could atleast double the poor performance of the current setup?

what else could i do to make sure before i go bying a $300 motherboard for its pci-x slot?

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I used to have that perc3/1600 card in a 32bit slot and received similar disappointing results. My old 40gb WD IDE drive in the same computer would consistantly outperform the 2 10k Maxtor drives I set up in raid 0. Never tried it in a 64bit slot.

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I used to have that perc3/1600 card in a 32bit slot and received similar disappointing results. My old 40gb WD IDE drive in the same computer would consistantly outperform the 2 10k Maxtor drives I set up in raid 0. Never tried it in a 64bit slot.

thanx Dave but that sucks....

i've seen various posts in similar threads

suggesting the perc3/dc as a good value/performance u160 controller

is this ment to be good scsi performance?

lol , can't imagine what a crappy controller would give...

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I've had the 4 port version, enterprise 1600 quad channel in a 64/66mhz slot running 4 36gb MAS drives in raid 10 with much greater results than what you're posting. I never tried in a 32bit/33mhz slot though...

The 1600 had a number of options that either made it dog slow or a good performer. Make sure each of your drives are initiated in the proper termination (LVD 160) and that nothing is forcing the drives to perform at lower bus speeds.

Enable Write back cache, adaptive read ahead, and few other options I was able to tweak the 1600 to where it performed well.

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Make sure each of your drives are initiated in the proper termination (LVD 160) and that nothing is forcing the drives to perform at lower bus speeds.

as i said earlier i know very little about scsi....:huh:

could you explain it to me or give me a link where i can read about LVD160, proper termination etc?

thanx in advance..

Enable Write back cache, adaptive read ahead, and few other options I was able to tweak the 1600 to where it performed well.

wish i joined this forum earlier...

it took me three hours of step-by-step checking every single raid bios setting....:(

crosschecking it with atto & hdtach benchmarks to find out about those tweaks you mentioned....

thanks anyway shokunin :)

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update....

i read the very interesting thread about the WinXP bug with scsi disks...

tried to install dskcache but apparently the controller and/or drivers does not provide the required info..

so xpcachefilter is my only solution...

but unfortunately i can't find the manual install files

(tried the exe file but no luck...)

does anyone have these files?

thanx in advance

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as i said earlier i know very little about scsi....:huh:

could you explain it to me or give me a link where i can read about LVD160, proper termination etc?

thanx in advance..

Slacker,

In the bios, there should be a display that shows all the SCSI channels and you'll see a bunch of empty ID's but the 2 drives should be in there somewhere. You should be able to identify the "speed" of the bus by U160, or UW, SCSI2, SCSI3, etc. Hopefully your drives are in LVD or U160 mode. If not then change it to U160. If you can't change it, then it's possible that you have a bad cable or improperly terminated cable.

Your SCSI cable should be "terminated" aka there should be a small plastic box or device at the end of the cable...

update....

i read the very interesting thread about the WinXP bug with scsi disks...

tried to install dskcache but apparently the controller and/or drivers does not provide the required info..

so xpcachefilter is my only solution...

but unfortunately i can't find the manual install files

(tried the exe file but no luck...)

does anyone have these files?

thanx in advance

I've not used the XPcache filter but the link is still alive in the thread below (not the 1st hyperlink, but the second one)

http://forums.storagereview.net/index.php?showtopic=11702

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Slacker,

In the bios, there should be a display that shows all the SCSI channels and you'll see a bunch of empty ID's but the 2 drives should be in there somewhere. You should be able to identify the "speed" of the bus by U160, or UW, SCSI2, SCSI3, etc. Hopefully your drives are in LVD or U160 mode. If not then change it to U160. If you can't change it, then it's possible that you have a bad cable or improperly terminated cable.

Your SCSI cable should be "terminated" aka there should be a small plastic box or device at the end of the cable...

yeap i've placed the plastic jumper on the one Maxtor

and the channels properties both appear as U160 mode

I've not used the XPcache filter but the link is still alive in the thread below (not the 1st hyperlink, but the second one)

http://forums.storagereview.net/index.php?showtopic=11702

unfortunately the link is working but contains the full version of XPcache filter

and not the manual install files...

thanx alot for your help shokunin

but i think i'll try the raid array with Windows 2003

to see the performance cost of the WindowsXP bug

i'll post the updates as soon as my Win2003server installation finishes

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The thing that 2k3 will do for you is allow the os to enable the cache on disk flag.

Something else to be sure of is that each channel in use is terminated. Each individual cable must have termination, in raid0 with two drives on a dual channel controller you want one drive per channel to spread data acess.

Also, the 1500 is reputed to be better at 32bit slots than the 1600.

Some thoughts for you.

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The thing that 2k3 will do for you is allow the os to enable the cache on disk flag.

Something else to be sure of is that each channel in use is terminated. Each individual cable must have termination, in raid0 with two drives on a dual channel controller you want one drive per channel to spread data acess.

Also, the 1500 is reputed to be better at 32bit slots than the 1600.

Some thoughts for you.

thank you very much for the useful thoughts

i intend to use the LSI1600 on my arriving-soon asus 975x motherboard on a 64bit pci-x slot...

for the moment i'm just trying to find the best configuration on my second system's pci (abit max-3)

Something else to be sure of is that each channel in use is terminated. Each individual cable must have termination, in raid0 with two drives on a dual channel controller you want one drive per channel to spread data acess.

i curently have both maxtors on the same channel

both channels are U160 and properly terminated

Do you mean that it would be better if each hdd was connected to a seperate channel with its own cable?

(never thought of that to be honest)

is this really gonna have a performance impact worth the fuss and cost?

thanx again for your input

and i really look forward to see your answers

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Do you mean that it would be better if each hdd was connected to a seperate channel with its own cable?

(never thought of that to be honest)

is this really gonna have a performance impact worth the fuss and cost?

anyone? :unsure:

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Best option for you would be to leave the 1600 alone, and get a LSI 20320-R, 21320-R or 22320-R.

These aren't full raid controllers but will do hardware raid 1 or 0 (make sure the cards extension is -R)

These cards aren't expensive and will provide you with a much better performance.

(I have the 21320-R with 2 Maxtor Atlas 10KIV 36GB in RAID0 on one channel in PCI 32/33slot on Asus NForce 2 board)

I get 80MB/s without a problem.

The only faster raid controller currently on the market for my raid0 setup is the LSI Megaraid 320-2X / 320-2E (and copied versions as intel SCRU42X and SCRU42E) and thats expensive. Since I don't need raid 5/10 and multiple raids getting a LSI scsi card with raid option is very good, much better then adaptec hostraid scsi cards.

I honestly don't think putting each drive on a separate channel will help your problem, though it will be better for performance it seems your problem is something else.

Did you install Win2K3+SP1, if so what happened to performance ?, if not please try.

Make sure you set the "enable write chaching on the disk" option in the device manager for your harddisk.

The enable enhanced performance option didn't give me a significant increase in speed with my setup so I left it off.

Also make sure you enable write-back cache in the raid controller, if you can only select write-through means you need to install a batterybackup option, some raid controllers require you to use a battery backup before you can slect write-back.

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thanks alot you for your input AeroWB :)

Did you install Win2K3+SP1, if so what happened to performance ?, if not please try.

Make sure you set the "enable write chaching on the disk" option in the device manager for your harddisk.

The enable enhanced performance option didn't give me a significant increase in speed with my setup so I left it off.

Also make sure you enable write-back cache in the raid controller, if you can only select write-through means you need to install a batterybackup option, some raid controllers require you to use a battery backup before you can slect write-back.

I installed Win2k3 sp1 but i can't change the power options in the PERC3/DC properties

as the raid array host the OS.

besides there is only one option there, which is grayed out and set to enable by default

the other thing i did was to convert the disk to dynamic

but i indeed saw a performance difference, not something significally better though

(now its 70mb/s burst 60mb/s avg @7.7ms r.a.t.)

Best option for you would be to leave the 1600 alone, and get a LSI 20320-R, 21320-R or 22320-R.

These aren't full raid controllers but will do hardware raid 1 or 0 (make sure the cards extension is -R)

These cards aren't expensive and will provide you with a much better performance.

(I have the 21320-R with 2 Maxtor Atlas 10KIV 36GB in RAID0 on one channel in PCI 32/33slot on Asus NForce 2 board)

I get 80MB/s without a problem.

The only faster raid controller currently on the market for my raid0 setup is the LSI Megaraid 320-2X / 320-2E (and copied versions as intel SCRU42X and SCRU42E) and thats expensive. Since I don't need raid 5/10 and multiple raids getting a LSI scsi card with raid option is very good, much better then adaptec hostraid scsi cards.

i'll wait a little bit to test the controller on my new mobo's pci-x slot and see what happens...

if it does not - at least - match the performance of my raptors NF4 raid 0

(200mb/s burst - 100mb/s avg @ 8.6ms r.a.t.)

i'll definitely buy another controller... (i'll google the ones you suggested before to see prices etc)

I honestly don't think putting each drive on a separate channel will help your problem, though it will be better for performance it seems your problem is something else.

so is there even a small performance gain from such an action or not?

you understand that i need to try to get the best out of the perc3/dc

before i go looking for a substitute so....

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ok i got my new motherboard last night and tried the perc3/dc controler on the pci-x slot....

altough the results were better i think they are still behind both my single WD KS250 and the 2x36gb raptors raid 0..

the best HD tach i got was about 70mb/s burst and 65mb/s average....

and also i tried a little experiment...

i took the one Maxtor off the array and set up the other one as a single independent hdd..

guess what..

the same results... (only ATTO32 showed some performance decrease)

is this possible? same burst and avcerage read with 1hhd vs 2x(raid 0)

what else can i try before bying another controller (u320 this time)

thank you in advance

and i look forward to your replies

(i'm so close to smashing that damned perc3/dc ....)

Edited by SlackerXL

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Ok slacker I got some news, its not a "poor performing raid 0" its simply a raid 0 performing as raid 0 arrays do, you would be faster (or the same) going with a single drive on your onboard controllers, imagine that for a lot less money get the same performance, strange but true, I type this to much so read these threads and read this whiic quote, just get a single drive man your friggin wasting your time and money. :(

"Pathetic? Actually, no. SCSI disks were never intended to have programs installed on them. They are meant for storing data reliably and responding quickly to read and write commends issued by multiple users concurrently. What is pathetic, is that people are stupid enough to buy these high-$$$ server drives for "the Xtreme Hardcore Gaming Performance."

Read this one for sure:

http://forums.storagereview.net/index.php?showtopic=21862

This one has some good information for you near the end:

http://forums.storagereview.net/index.php?showtopic=21895

Good Luck. :)

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Hey SlackerXL,

The fact that using one or two disks doesn't make a difference, means that the bottleneck ain't the disks, or that the benchmark has no profit from raid 0.

I found some benchmarks on the LSI Megaraid E1600 where the tested with a couple of Maxtor 15K's, all atto benches for reads were around 140MB/s and writes 65MB/s.

They tested raid 1, 10 and 5. and Raid 5 was tested with 3,4 and 6 disks. and since all the results where all within 2MB/s it seems the controller is really limiting the system.

Their config:

HDD cache modus Write-back

Controller cache modus Write-back

Controller cache geheugen 128MB

Controller strategie Adaptive read-ahead, direct I/O

Stripe size 128KB

Array status Optimal

Controller tested in PCI-X slot on Intel E7525 chipset.

I don't know if they used both channels or not, but maybe using two channels will improve your results.

It's too bad they don't have benches of the LSI2x320-R series of cards butt only the much more expensive MegaRAID's.

xSTLx, I agree with you that not all setups do profit from Raid 0. Also SATA disks connected to the onboard controllers have the best price/speed ratio. So for most people that is the way to go. If your setup benefits from raid 0 depends on what you do with it, it is heavily used in video-editing workstations since it uses a lot of lineair data reads/writes and their raid 0 really benefits.

About using SCSI disks in workstations I do not agree with you, "SCSI disks were never intended to have programs installed on them" is completely incorrect! SCSI disks have always been used in the high end computing systems for all tasks, also in worksations. SCSI disk have always been superior to ATA in every respect, the only reason ATA was used so widely was because of the costs. Now that SATA is on the market the difference is smaller in some area's and WD's raptor is the only ATA drive that can outperform SCSI in some single user areas. Off course I compare the same generation equipment, five year old SCSI equipment will perform badly compared with current gen ATA.

If one is willing to benefit from SCSI, he should really get currrent generation stuff, otherwise you will be disappointed. This is exactly Slackers problem here.

Also SCSI devices are less CPU dependent then SATA and SATA much better then PATA. This aspect comes in handy in multi tasking.

SCSI disk are much more reliable then SATA/PATA drives, I have used more then 30 different disks in my systems and have only had two SCSI drives failing (have used about 16 SCSI ones) and more then ten ATA drives failed on me (I've had about 22 ata drives)

Also a few years ago I build two identical computers the fist one with a SCSI disk (Maxtor Atlas 10K 9GB) and SCSI opticals (plextor/yamaha) and the second one with a PATA disk and ATA opticals.

I never thought the difference was that big!! It was huge!!!. When I only used one program at a time, there was no notable difference between both systems. but when I was multitasking it was notable:

A) when copying files from cd to hdd I could still work normal on my SCSI system while almost not noticing big delays etc. (using Internet/mail/playing music/excel etc) The ATA system became reallly slow while coping so runnning programs was no fun (yeah I had all UltraATA drives, enabled and had 512Mb of RAM using Win2K)

B) On my all SCSI system I could do these things in parallel: Copying Rarred iso from my FTP to my workstation, extracting the previous rars to iso, burning the previous iso to cd, play mp3 and browse the internet, though I noticed delays, it worked quite good. The ATA systems would stop working correct when I started the 3th thing: burning cd's, the cd's were only usable as coasters. and I wasn't even playing MP3's and browsing.

Since then I have build my workstions completely ATA free, today my opticals are ATA since I cannot buy current gen. SCSI DVD-RW's which is a shame, but my disks will be SCSI, always!

Edited by AeroWB

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