Need help, SCSI throughput less than expected?

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Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
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I like to keep my posts short and to the point, so I'll leave out a lot of background info unless someone specificly asks for it.

Alright, so, I started off with this:
http://home.earthlink.net/~eckyx3/images/scuzzy.jpg

3x of these drives: http://www.seagate.com/support/disc/specs/scsi/st39204lw.html
1x Adaptec 2940UW http://www.adaptec.com/worldwide/suppor...language=English+US&prodkey=AHA-2940UW
1x LSI SCSI adapter (never bothered to look it up)

Free.

Right so anyway, I did some benchmarks, and they were pretty well the same with 1 drive, or 3 drives raided. About 37MB/s, same across a series of benches I used. Understandable, considering the card was limited to 40MB/s total.

So, I purchased a 29160. a new cable, and an LVD/SE terminator. And my results were the same.

http://home.earthlink.net/~eckyx3/Hard%20drive/scsi%20raid.JPG

To say the least, I was disapointed. I did some research, thinking maybe the PCI bus itself was limiting me, or something. I tried putting each drive on a sepperate connector on the card. Same deal. Yes, I was disapointed. Certainly not faster than my SATA WD SE 120gb.

http://home.earthlink.net/~eckyx3/Hard%20drive/C%20drive.JPG

So, on a hunch, I tried all 3 drives each on their own card, one with an old terminator I had, one using a random 7200rpm 8gb to terminate the line, and the last with my new cable/terminator. My results were much better.

3x Cheetah:
http://home.earthlink.net/~eckyx3/Hard%20drive/scsi%20raid.JPG
http://home.earthlink.net/~eckyx3/Hard%20drive/scsi%20raid%202.JPG

WD SE 120gb SATA:
http://home.earthlink.net/~eckyx3/Hard%20drive/C%20drive.JPG
http://home.earthlink.net/~eckyx3/Hard%20drive/C%20drive%202.JPG

I was quite impressed. For a total sum of $40 (what I paid for the 29160) I have performance beyond a single raptor. Mind you this is using XP's software raid, and on 3 different cards. I'm sure performance would be a heck of a lot better if I had 3 matching cards/terminators, and/or used hardware raid. But I am still stumped as to why I don't get more than 40MB/s with all 3 drives on the 29160, it makes no sense! Any ideas? Did I forget to do something?
 
F

fuzzynavel

Senior member
Sep 10, 2004
629
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Originally posted by: Yuriman
I like to keep my posts short and to the point, so I'll leave out a lot of background info unless someone specificly asks for it.
Click to expand...


LOL you lied!! bump for you anyway!
 
Markfw

Markfw

Moderator Emeritus, Elite Member
May 16, 2002
27,427
16,294
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OK< it looks to me like you SCSI at ~40 is loosing to the SATA at ~50. Your seek times would be better than the raptor though. I found the same to be true, until I got PCI-X, than my array was free ! 200k read/write with 5 of your drives in raid0.
 
Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
106
Originally posted by: Kensai
INTERNAL FORMATTED TRANSFER RATE (MB/sec)_26 to 40
Click to expand...

That's from Seagate's site with the specs on those drives.
They're old drives.
Click to expand...

Yes. I know. In summary of what I said, the drives bench about 34MB/s alone, and when you have all 3 raided on 1 card they bench at about 35MB/s. With all 3 on sepperate cards, they bench at about 80MB/s.
 
Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
106
Originally posted by: Markfw900
OK< it looks to me like you SCSI at ~40 is loosing to the SATA at ~50. Your seek times would be better than the raptor though. I found the same to be true, until I got PCI-X, than my array was free ! 200k read/write with 5 of your drives in raid0.
Click to expand...


Certainly, and the 3 drives sepperatly beat the heck out of my SATA drive. The problem is, I don't have 3 free pci slots and I have to take things out. I'd like to get full speed from a single card, and some of the greatest minds on other web communities cannot understand why I don't. All 3 drives are LVD/SE and U160, as is the card, and I have an LCD/SE terminator.
 
mechBgon

mechBgon

Super Moderator<br>Elite Member
Oct 31, 1999
30,699
1
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1) My Atlas 15k II pwns j00 :D

2) On the 29160, are you aware that one of the two 68-pin plugs is not an LVD channel? Use only the plug towards the rear of the card.

3) Is your cable and terminator Ultra160 or Ultra320 stuff for sure, twistie-strand LVD cable with an LVD terminator?

4) What motherboard are you using and what PCI slot is the card in?

5) Is terminator power enabled on at least one drive?

6) Toss the old UltraWide card(s), that's like having a car stereo that takes 8-track tapes :D

7) Try the Adaptec EZ-SCSI software's SCSI Explorer if you got it with the 29160. See what the true state of your SCSI bus is.
 
Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
106
1) My stuff was free.

2) Yes. I have tried both channels.

3) Yes.

4) I tried it on my DFI nF4 Ultra-D, my friend's nForce3, and my dual Pentium Pro 200mhz. I have tried all available pci slots.

5) No. I am fairly new to SCSI, but nobody had yet mentioned it. Is it needed?

6) I have a ton of old drives that won't do anything near 40MB/s, but they are useful as mass storage.

7) Do I want it for Windows 95, 98 or NT?

EDIT: Actualy, could you show me specificly what software to get?

http://www.adaptec.com/worldwide/suppor...y%2FSCSI+Software&fromPage=driverindex

I have the latest drivers for both adaptec cards.
 
mechBgon

mechBgon

Super Moderator<br>Elite Member
Oct 31, 1999
30,699
1
0
EZ-SCSI would come packaged with the 29160 in its retail box, so I thought maybe your seller might've included it. If your throughput is topping out at the 40MB/sec mark then it sort of hints that maybe the bus is stuck down at SE speeds, so try enabling terminator power on one of the drives to power the terminator, just in case the card isn't managing it.

I really think you're having a case of overly-high expectations if you think three old drives are going to get you monster throughput on one bus. But on the flip side... if you want high performance, you're about $199 away from it, now that you have the 29160, cable and terminator. That'll get you a current-generation 15k 36GB drive or a current-generation 10k 73GB drive, about the same price as a 74GB Raptor.
 
bob4432

bob4432

Lifer
Sep 6, 2003
11,727
46
91
you also have to understand that those drives are a at least a couple generations old, i am not sure how old, but they are definately not current get. this will be part of the problem. when were your drives made? they should say on the hdd itself. if you have 2x18GB 15krpm u320 hdds and were not maxing out a 32bit pci slot that would be a worry, but for the age of your equipment, what you are getting is definately acceptable. if you really want i can bench a 9GB 7200rpm ide hdd that is probably within the same production time as your scsi hdds for a fair comparison.

also, software raid is not the best idea. for performance and since you have the 29160, you would be best off to get a 36GB 15krpm u320 hdd, it will beat these 3 hdds, if that is what you are looking for.

comparing 3-5yr old scsi hdds to a relatively new ide hdd is not too fair of a comparison. it is like comparing a 450MHz AMD K6-2 to a A64 3000Venice....sure they are still cpus but with many generations of upgrades in the A64.

that being said, with those hdds, if you just used a single hdd, they will feel faster than your 120GB hdd due to their seek time, unless you are transfering large files.

[EDIT] THIS WAS WRITTEN BEFORE READING mechBgon's 08:55PM post....
 
Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
106
He included a bunch of floppy disks that I never bothered to look at, since I don't have a floppy drive. One of them has :

Ultra 160 Family Manager set v1.10
Microsoft Windows NT 4.0
Version: d3.4
Microsoft Windows 95/98
Version: d3.4
DOS ASPI
Version: 1.06

I am assuming that is the one you mean? I'll copy it over to my pc tomorrow.

@my expectations for these drives, I was not expecthing monster speeds from them. I am just curious about scsi, and I was even more curious as to why I get ~80MB/s by having them on 3 sepperate cards, and only 40MB/s on a single card, which should not be the case. I know they are ancient (not sure how old though, but for the price, $0, I cant complain), but its a good way to learn.
 
mechBgon

mechBgon

Super Moderator<br>Elite Member
Oct 31, 1999
30,699
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That appears to be a driver diskette, not EZ SCSI. I might still have my EZ SCSI diskettes from my old 19160, I'll rummage around at work tomorrow.
 
Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
106
Googer

Googer

Lifer
Nov 11, 2004
12,576
7
81
Your SCSI Adapter or HBA (Host Bus Adapter) is a major bottleneck here, the Adaptec 2940 line is only capable of 40MB/s per channel you card (I have one sitting in my closet) the Adaptec 2940UW is a two channel HBA on newer Ultra 160 Hard Drives. My advice is to go on ebay and Pick up an Ultra 160 LSI MegaRaid HBA for less than $20 I will find a few and post some links. Newer U160 HBA's are able to transer data much faster and support TCQ and NCQ that are not avalable on the 2940UW along with a ton of other features. You will instantly notice the differance.


EDIT: I missed the part where you said you now have a 29160. OOPS :eek:
 
Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
106
Which of those would you recomend? I assume you mean the first one. But... I have heard that hardware raid controllers often perform worse than software raid. Many of the older hardware raid controllers claim 80 to 160MB/s, but in real world only get about 45MB/s.

What do you think?
 
bob4432

bob4432

Lifer
Sep 6, 2003
11,727
46
91
Originally posted by: Yuriman
I am not using a 2940uw...

And now that I have my array tweaked up, I have 2 words to describe it. HOLY SH*T.

http://home.earthlink.net/~eckyx3/Hard%20drive/fixed2.JPG

Take that Raptor!!!!

Looks like the 1024 (KB? MB?) chunk's read speed was limited by the PCI bus.

:shocked:
:confused:

What was that about expecting too much from old drives?!
Click to expand...

i must say i am surprised....but happy for you :) good deal. are they loud?
 
bob4432

bob4432

Lifer
Sep 6, 2003
11,727
46
91
Originally posted by: Yuriman
Which of those would you recomend? I assume you mean the first one. But... I have heard that hardware raid controllers often perform worse than software raid. Many of the older hardware raid controllers claim 80 to 160MB/s, but in real world only get about 45MB/s.

What do you think?
Click to expand...

weird, i have only heard the opposite.

also, since you are running a striped raid, make sure you back that up often, because your chances are now 3x more likely there will be a hdd failure to take out your drive.

this has been an excellent learning too for you :) now, scsi is not that hard is it? i wish other people would try it out. once you go scsi you never go back :D
 
Yuriman

Yuriman

Diamond Member
Jun 25, 2004
5,530
141
106
They are what I would consider loud, yes, but the type of noise they make does not carry. As long as you insulate them from the case, they are pretty quiet, and if you box them in foam with only the sides showing (for airflow) they are no louder than anything else in my pc.

And... since I'm posting, I might as well share a few other things I have done recently.

http://home.earthlink.net/~eckyx3/Oh%20teh%20noes,%20heatsink
http://home.earthlink.net/~eckyx3/Oh%20teh%20yes,%20Heatsink
http://home.earthlink.net/~eckyx3/Ohh%20teh%20yes,%20CPU
 
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