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Advice to understand/improve performances

Last response: in Storage
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January 13, 2011 8:28:27 AM

Hi,

I am looking for advice/opinion from experienced users on improving the performances of my RAID 0.
I am not confortable with reading hardware specifications as my knowledge in this domain is quite poor and even less comfortable to interpret data :( 

I currently have 4 old HDD Samsung HD502IJ (Sata 2, 500GB, 7200RPM, 16MB cache) in a RAID 0 Array controlled by a Promise FastTrack 4660 PCIe x4 on my motherboard, Gigabyte GA X48 DQ6. Here is the datasheet of this Promise. The HDD can do 175MB/s (300MB/s when accessing the buffer) according to this spec. The promise card can do up to 750MB/s.

I did test my RAID 0 array with HD Tach and I get an average Read of ~225MB/s.




I am disappointed when I compare to my RAID 5 array, built with 6 recent HDD Samsung HD204UI (Sata 2, 2 TB, 5400RPM, 32MB cache) on the intel controller of the motherboard. These HDD can do 250 MB/s (300MB/s when accessing to the buffer) according to this spec.




I was expecting the RAID 0 to be faster than the RAID 1 (most due to the feeling of a non-skilled user than due to any concrete facts).

My understanding is that the bottleneck is not the Promise FT 4660 (If it is: any opinion on the HighPoint RocketRaid 2310 for a "personal usage" ? ).

It seems to me that the bottleneck is more with the old Samsung HD502IJ...
However, couldn't I expect more that 225MB/s with 4 HDD with 175MB/s in my RAID 0 ?
Both for the RAID 1 and RAID 5 I have enabled the various caching features available. However, I have not enabled NCQ as it seems to be slower if I do that.

I want to improve the RAID 0 because, as a software developer, I use it to run several VMWare test machines.

Thanks a lot for any concrete (not too technical) advices.

O.
a c 180 G Storage
January 13, 2011 12:38:39 PM

Raid-0 is of benefit when performing sequential operations on large files. That is what synthetic raid-0 benchmarks show.
The problem is that typical desktop operations do not work that way. Typical OS operations are mostly small random reads and writes. I would expect that to also be true of VM machines.
Here is an older article on the value (or lack thereof) of raid-0 in normal desktop operations:
http://www.storagereview.com/php/cms/cms.php?loc=news_c...



If you want great performance, look into using a good SSD.

Look for the gen3 products which should launch soon.
January 13, 2011 5:48:22 PM

Thanks for the advice and the link. This is very interesting...

Regarding the use of SSD, the price (at least in Europe) is still to high for me. 240Gb is ~750€ (~1000$)...

O.
a c 180 G Storage
January 13, 2011 7:44:51 PM

ogegoon said:
Thanks for the advice and the link. This is very interesting...

Regarding the use of SSD, the price (at least in Europe) is still to high for me. 240Gb is ~750€ (~1000$)...

O.

The gen 3 SSD products will be cheaper per gb, and also get somewhat better performance. It will probably pay to wait. It is currently a very competitive market.
!