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RAID 0 Slower that single drive??

Tags:
  • Hard Drives
  • NAS / RAID
  • Controller
  • Storage
Last response: in Storage
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April 7, 2003 1:53:57 PM

Hi:

I've an Asus A7V333 with 512MB DDR333 and a Athlon XP 2000+.
On primary controller i've a Seagatte Barracuda IV of 60GB.
On the RAID controller (Promisse) i've 2 Maxtor Diamond Plus 9 of 80GB each on a raid 0 configuration.

Well, this 2 drives on this configuration are extremly slower than the seagatte drive alone. Anyone can explain why?

Just to see the diference, the seagatte when qriting is able to go till 38MB/s, and the Maxtor's only achive 20MB/s, sometimes falling to 10MB/s..How can this be?

I'm using Windows 2000


Regards

Be sure to engage your brain before open your mouth!

More about : raid slower single drive

April 7, 2003 3:08:24 PM

That is very strange... have you got the latest BIOS and drivers installed for the RAID controller? Is ATA66 enabled in Win2k?

And do you know in which DMA mode the RAID array is running? And which block size did you choose?

My dual-PSU PC is so powerfull that the neighbourhood dims when I turn it on :eek: 
April 7, 2003 4:16:42 PM

Check the following:
1) The jumpers on these disks should be set to master
2) Both disks of your RAID 0 array should be connected to independent (one for each disk) ports of the Promise controller.
3) Check that the IDE cables are not loose and that they are 18 inches or shorter
4) Defrag your stripped array and then run again the benchmarking software.


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It's not important to know all the answers, as long as you know how to contact someone who does.<P ID="edit"><FONT SIZE=-1><EM>Edited by gaviota on 04/07/03 12:23 PM.</EM></FONT></P>
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April 7, 2003 7:09:20 PM

Hi:

1) Just did that yesterday. They were in cable select, i switched them to master
2) They are. Each one is on each of the avaible ports
3) Not sure abou this, but they are 80 conducters cables and all most sure they are smaller that the 18 inches
4) Only 7GB is being used...Doesn't seem the be needed for defragmenting with so little space ocupied...

The srantge thing is that when i first tryied to build an raid, i used Seagatte ATA IV hard disks...Then i read somewhere that there was a incompatibility from this disk with raid systems, so i changed them to Maxtor... No luck i guess..still to slow...



Be sure to engage your brain before open your mouth!<P ID="edit"><FONT SIZE=-1><EM>Edited by jrosado on 04/07/03 03:11 PM.</EM></FONT></P>
April 8, 2003 5:19:10 PM

The Barracuda IV HDs from Seagate have very bad RAID 0 performance... they're even slower then a single drive.

But I never heard of Maxtor having the same problem... did you check on which DMA mode the drives are running according to the Promise BIOS?

My dual-PSU PC is so powerfull that the neighbourhood dims when I turn it on :eek: 
April 9, 2003 12:39:12 PM

Hi:

Yesterday i found a modified BIOS to my A7V333 that allows to have full Promisse RAID BIOS. This allowed to change the srtipe size. The best strip size i found was 16KB. My reading performance in HDTach increased from 45MB/s to 80MB/s!!! However writing perfomance still is arround 25MB/s :( (

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