Can you Stripe 3 Drives Together in a RAID ?

Discussion in 'macOS' started by fab5freddy, Apr 6, 2009.

  1. fab5freddy macrumors 65816

    fab5freddy

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    #1
    Is it possible to Stripe RAID 3 Drives together ?
    to make the drive go faster..

    As in Striping 2 drives together in a RAID ??

    2 x 7200 RPM drives = 15,000 RPM drive

    = 3 x 7200 drives = 21,600 RPM ?
     
  2. Boneoh macrumors 6502

    Boneoh

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    #2
    Yes. I am running 3 WD VelociRaptors in a RAID 0 stripe for my User files in my Mac Pro. Performance is great :D

    I ran the diglloyd disk test benchmarks, here is a link. Look for the User volume. The OS volume is an Intel X25-M SSD drive.

    http://forums.macrumors.com/showthre...er#post7255329
     
  3. fab5freddy thread starter macrumors 65816

    fab5freddy

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    #3
    Then i guess you could Stripe 4 or 5 Drives together ??
    or even more ??
     
  4. Boneoh macrumors 6502

    Boneoh

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    #4
    At some point, you will reach a point of diminishing returns. Also, the more drives in a RAID, the more likely that one will fail. :( In RAID 0, that means you will need to recover from a backup. RAID 0 has no redundancy.

    Check out wikipedia for more RAID info, the explanations are very thorough. :)
     
  5. Tomorrow macrumors 604

    Tomorrow

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    #5
    If you're going to use 4 drives you might consider RAID 10 or RAID 5, or RAID 5 with five drives. You lower your cost per megabyte, and maintain redundancy.
     
  6. fab5freddy thread starter macrumors 65816

    fab5freddy

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    #6
    I just want a SUPER FAST BOOT DRIVE on my Mac Pro.
    So could i Boot from a 3 drive "Striped RAID" ?
     
  7. Tomorrow macrumors 604

    Tomorrow

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    #7
    Yes, but:

    (1) I'm not sure you'd see any performance benefit over striping 2 disks;
    (2) As Boneoh pointed out, you're increasing your chances of a failure, with no redundancy.
     
  8. Boneoh macrumors 6502

    Boneoh

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    #8
    Consider an SSD drive for your OS and Applications install. I'm using an Intel X25-M SSD, it is very fast. Search the forums here, there are lots of posts about it. :)
     
  9. dal20402 macrumors 6502

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    Apr 24, 2006
    #9
    Sure, but it would be stupid.

    Latency (how fast you can start accessing data) matters much more than throughput (how fast the data flows once you are accessing it) for a boot drive, because you're reading lots of tiny files.

    RAID 0 improves throughput, but not latency, because the drives still have to rotate to reach the beginning of each file, and they are still rotating at 7200 rpm.

    High throughput is more useful for things like working with video in real time, which is why most people use RAID 0 arrays for data rather than as boot drives.

    If you want a really fast boot drive, get an Intel X25-M. Or get an X25-E for even more speed if you can fit your OS and apps into 32 GB. Good SSDs (Intel, OCZ Vertex) absolutely kill hard drives on latency.
     
  10. Baron58 macrumors 6502

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    Feb 19, 2004
    #10
    You can stripe many drives together to form large volumes.

    See: http://www.ibeast.com/content/tools/RaidCalc/RaidCalc.asp
    Use RAID5

    However, your "RPM" idea is incorrect. Speed gains come from reducing head latency, which has NOTHING to do with the rotational speed (RPM) of the drives.
     

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