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  1. #1
    3 Star Lounger
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    RAID-0 (Win XP Home )

    I have a new PC with two 250 GB drives arranged in RAID-0 configuration, which therefore appears as one 500 GB drive in Windows Explorer. After loading software, etc., I analyzed memory on the "500" GB drive and found, as expected with RAID-0, the used portions split, with somewhat more than half near the low memory locations and the rest in the upper half (second drive, I presume; I'm not clear on how MS's Disk Defragmenter analyses and presents the information). After two runs of disk defrag (separated by installing additional large programs and generating large data files), almost all of the "used" portion shows up in the lower (I presume; left in the graphic presentation) portion of the memory. Have I lost the alternate-sector-access advantage of RAID-0? If so, can I restore it and how do I defrag without losing the RAID-0 speed advantage? If not, why was the original presentation split as one would expect, while the current presentation is essentially all in the left part of the graphic illustration?
    Thanks.

  2. #2
    Plutonium Lounger
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    Re: RAID-0 (Win XP Home )

    What makes you think that lower addresses are on one drive and higer addresses on the other?

    The normal way that RAID-0 works is that alternate "stripes" are on each drive, with a typical stripe size of something like 4 MBytes. So the lowest 0-4Mbytes is on drive 0 and then 4MB to 8MB is on drive 1 etc.

    StuartR

  3. #3
    3 Star Lounger
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    Re: RAID-0 (Win XP Home )

    I frankly do not know how the alternate stipes show up in disk defrag. All I know is that the first time I looked at what disk defrag showed, most of the files were in two groups, one at the left of the display (which seems to be low memory addresses) and the other beginning about half way "up" the display (toward the right of the diagram). After defrag, almost all of the files were compacted in the left-most portion of the display. So I wondered if I had destroyed the RAID-0 advantage. If not, great!

  4. #4
    Platinum Lounger
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    Re: RAID-0 (Win XP Home )

    You may be confusing the logical view (as shown by the defragmenter) with the physical view (as Stuart has described the disk organisation for RAID-0). The operating system knows very little about RAID-anything. I have RAID-1 at home, where two disks are mirrored as if they were a single disk, and at work we have servers with RAID-5 disks like there's no tomorrow!!

    Only when "unhappiness occurs", and you have a form of disk or controller failure, do you really need to think of the physical disks. Most of the time, you just treat it as one or more disk partitions of particular sizes, as you are presented by the defragmenter, for example. (Don't worry, be happy!).
    <font face="Script MT Bold"><font color=blue><big><big>John</big></big></font color=blue></font face=script>

    Ita, esto, quidcumque...

  5. #5
    3 Star Lounger
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    Re: RAID-0 (Win XP Home )

    Thanks to you both! No worries. I'm happy.

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