Advice to understand/improve performances

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.

http://img695.imageshack.us/img695/7556/promiseft4660raid0.jpg


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.

http://img547.imageshack.us/img547/4647/gax48dq6raid5.jpg


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.
3 answers Last reply
More about advice understand improve performances
  1. 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_content&id=970&start=6&range=10


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

    Look for the gen3 products which should launch soon.
  2. 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.
  3. 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.
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