Poor Raid 0 performance?

[Tran]

Hi, i have 2x 45gb IBM dtla 7200 rpm connected to my kt7a-raid

each drive is master on seperate controlers, and nothing else connected to the controlers
bios set for udma 5 and 16k raid block size
and of course raid 0 using NTFS

Sandra gives me 37000, other people are getting 45000+ with simlar setups, and hdtach is telling me crap:

12.6 ms seek time.. why is this not more like 8 ms?
burst speed 77 mb sec

seq speed:
average: 57mb
max: 75mb
minum: 13mb <-- W T F? if you look at the graph you can clearly see 7-10 times that the transfer rate drop down to 13-15 mb but only for a shot time..

whats up with this? btw.. cpu utilazation: 42% isn´t this a bit high?

These bences are taken with cpu idle

Specs:

CPU: AMD ThunderBird 1200MHz @ 1333MHz (10*133)
Motherboard: Abit KT7A-Raid
Memory: 256 MB of NEC PC133@cas2
Video Card: Creative Annhilator Pro (Nvidia Geforce DDR)
Hard Drive: 2x IBM Deskstar75GXP 90.0 GB @ 7200 RPMS
Monitor: 17
DVD Manufacturer &amp; Model: Compaq 4x
CDR/CDRW Manufacturer &amp; Model: Plextor 8x4x32
Storage Interface: IDE-RAID

Sound Card: SBLive 5.1 Platinum
Internet Provider: Simnet
Internet Connection Type: xDSL

Internet Connection Speed: 256/128 kbs
Operating System: Windows 2000 Pro
Other Components: 3com 3c905b 10/100
350w psu

Notes: Alpha PAL6035 Heatsink
Artic Silver thermal paste
Vantec System cooler
Sunon 80mm casefan

 

[Tran]

^bump^

 

[gcliv]

I'm not sure why you would be performing low compared to other people with the same setup, but Raid-0 is CPU intensive, so it's gonna hurt the performance some. Now if your system is just absolutely crawling I don't know what to tell ya. If you still want to keep some sort of security but want some performance, buy a third drive and make a stripe set with parity, Raid-5 isn't it?

 

[Tran]

don´t really care about secutiry

all i want is speeeed

 

[Sir Fredrick]

>>>>>12.6 ms seek time.. why is this not more like 8 ms?<<<<<

Because you're not running 10KRPM SCSI. Also, RAID has a negative effect on seek times.

 

[Marty]

I've found both HDTach and Sandra to be somewhat lacking when it comes to RAID. Try downloading this software from Atto. Its designed for SCSI controllers, but the benchmarking stuff should work for your system as well. Set the depth queue to a high level - this will give a test of real world server-type performance.

Marty

 

[rlism]

Sandra scores vary a lot with raid block size. Smaller RAID blocks will give higher Sandra scores - you get higher sequential read/writes, but some of your other scores will go down, like seek time. Larger blocks will give you performances closer to a single drive setup and better seek times.

I'm not too sure about the this, but I think Sandra scores also vary with partition size and if you've got yer 90 giggers, in a raid0, in one 180gb partition you'll probably see a performance hit cuz of that.

I'm guessing you're running windows98 or ME cuz you're cpu utilization is so high. If you're running 2000 it should run at mebbe half that. Still high but IDE RAID just sucks like that.

 

[gcliv]

Oops, my bad. I got it mixed up, I thot Raid0 was mirror, but you are currently striped, which should be the fastest. U might try just breaking the raid and going without.

 

[Tran]

i´m running win2k

and about the seek times, these disks are rated 8.5 ms and i have seen raid screenshots with two of these with 8 ms seek time

 

[Pariah]

Your drives are rated at 8.5ms seek time, not access time. You have to add latency, which is 4.2ms for a 7200RPM drive to get access time. So your 12.6 is actually a tad under the rated 12.7 access time.

 

[RGN]

Marty: Where should the numbers be?


I'm running a Promise FastTrack66 with a 5400 and a 7200 RPM drive... The 1024kb test gave 39199 read and 37532 write. Is this where it should be?

 

[Tran]

btw.. both partitions are defragged and i just tested them both again:

C drive, 7 gb
D drive, 80 gb


i should be getting 10k+ more compared to you guys

 

[RGN]

Your links aren't working...

 

[Tran]

they work for me


there have been some unstabilities with iceland -> usa connection today, try again?

 

[RGN]

Nope, can't get em...

Wow, Iceland... Is it cold there? I've never talked to someone from Iceland before.

 

[Pariah]

Your numbers look about right RGN, though I would strongly recommend against RAID'ing a 7200RPM and 5400RPM drive. You're crippling the 7200 by RAID'ing it with a 5400.

 

[RGN]

Pariah: Why? I don't understand why that that is crippling?

 

[Tran]

because raid always runs as slow as the slowest drive, to keep them in sync

and its not so cold in iceland.. very stable temps here all year round
right now 5°c

 

[Pariah]

The main benefit to buying a 7200RPM drive vs a 5400RPM drive is that the faster spindle speed lowers access time. In today's hard drives, access time has a much greater impact on performance than does transfer rates. By RAID'ing a 5400 with a 7200, the 7200 drive is slowed down to the access time of the 5400, thus eliminating it's greatest benefit.

 

[RGN]

Tran: 5 degrees C? NICE! I'm near Chicago, and its colder than that here!

thanks for the heads up on the speeds!!

 

[Tran]

^bump

anybody that can tell me how i enable udma in win2k?

 

[Pariah]

It's in device manager under the individual channels of the IDE controller.

 

[Tran]

can´t find it..

you are talking about when i ddbclick on the hard disk drive in device manager, right?

i´m not using ordenary ide channels, i´m using hpt370 raid

 

[Pariah]

If you're using a third party controller like yours, it should be enabled by default, and is not OS controllable. When your system boots, watch the HP BIOS boot process, it should tell you what UDMA revision each drive is using.

 

[desoca]

Don't worry about UDMA. The HighPoint drivers already take care of this.

Your problem may lie in a different area.

Are you using ACPI. Win2k will use this by default and lump everything on one IRQ, therefore adversely affecting performance.

Check this site out (under the BIOS section)on how to disable it:

ABIT KT7 FAQ