Anyone setup a RAID 10 with four 2 TB WD Blacks or Greens?

Discussion in 'Mac Pro' started by oban14, Dec 14, 2010.

  1. oban14 macrumors 6502a

    Joined:
    Jan 4, 2008
    #1
    Basically this would create a big 4 gig array that I could split into multiple partitions. I'd have mirroring and fast performance.

    I was wondering what the performance difference would be between the Greens and Blacks - Greens are known for worse performance, but I was wondering if in RAID 10 it would even matter.

    Anyone try something like this?
     
  2. alust2013 macrumors 601

    alust2013

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    Feb 6, 2010
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    On the fence
    #2
    The greens have variable spindle speeds, making them less than ideal for RAID setups. That can cause major lags in performance, so I would go with the blacks
     
  3. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #3
    Blacks will be faster.

    Take the single disk speed, and double it (performance is still a 2x disk stripe set).

    In the case of the Greens, they will be slower, and the set even more so. For example, lets say the Greens are good for ~78MB/s, so the set would be good for ~156MB/s (reads, but the same for write and random access throughputs as well). Now figure the Blacks are good for 109MB/s, so the set would generate ~218MB/s (reads).

    I know the information in the ads and datasheets gives this impression (marketing info), but it's not stated that way on the specifications section (nothing that says something like: RPM = variable or 5400 - 7200).

    And there's independent data out there that indicates they in fact run at a fixed speed (~5900rpm). A variable spindle would actually make things more complicated, and not be able to be cheaper than their faster rpm cousins (which are all fixed speeds). ;) At best, my guess is that the "variable" speed is when the vibration sensor has enough of a signal that it reduces power/shuts down the spindle motor until it's within vibration spec range (just as Enterprise models do). But it's for power reasons in this case, not stability. Quite cheap due to systems engineering, and they also save money on the spindle motors and servos not needing to be as fast (allows for the sensor cost, and still come in cheaper).
     
  4. Honumaui macrumors 6502a

    Joined:
    Apr 18, 2008
    #4
    the multiple partitions part ?

    if you are accessing those at the same time it might be slower than other setups ?

    analogy of a two drawer filing cabinet every other paper you have to close one drawer open the other put away repeat

    so be careful of partitions in use at the same time on the same physical setup


    good use of partition is say a 2TB drive with a outer 200 gig for scratch use the inner being used for backup

    bad use 200 outer for boot inner for storage of files !

    :) just good info to think about
     
  5. nanofrog macrumors G4

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    May 6, 2008
    #5
    Good catch. :) I missed this part. :eek:
     
  6. Eclipse278 macrumors regular

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    Jan 21, 2007
    #6
    Why do you want to mirror data? I hope not to protect your data. Time machine is better for that.

    [​IMG]
     
  7. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #7
    My RAID0 (two disc) out of WD20EARS used to transfer roughly 200MB/s when it was empty. Now it is about 70% filled and is still good for 150MB/s.
     
  8. flatfoot macrumors 65816

    Joined:
    Aug 11, 2009
    #8
    To the OP:

    Disk Utility won't let you partition a RAID set. You'd have to partition the individual disks first and then RAID the corresponding partitions.
     
  9. oban14 thread starter macrumors 6502a

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    Jan 4, 2008
    #9
    I'll have to do more research. Basically I wanted to maximize size, speed, and resiliency. I thought mirroring two RAID 0 volumes (making it RAID 10) would be a good mix of price and performance.

    The other volumes... OSX, boot camp, and as big/fast an "audio" partition I can have. I'm currently using two blacks to make a 4 TB RAID 0 partition but would like a bit more resiliency.

    I keep backups but I'd like to avoid doing restores. I'll take a chance on a hard drive failing before a controller or two failing at once. This isn't for anything mission critical, but I'd rather swap a drive and let it mirror than restore everything from backup.

    I was thinking I'd set up two of the disks as raid zero, then mirror the whole thing.
     
  10. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #10
    I used the real world figures from the 1TB versions in the example (couldn't quite recall real world for 2TB Green, did for 2TB Blacks). ;) I didn't bother to look up the 2TB Greens as I know they're still slower than the Blacks. :eek: :p

    As per your case, keep in mind as you continue to fill it, the avg. throughputs tend to nose dive much past the 70% mark or so.
     
  11. Honumaui macrumors 6502a

    Joined:
    Apr 18, 2008
    #11
    that is actually called raid 01

    you want 10 so you want to create two sets of raid 1 and then combine those with raid 0

    this way is a bit safer as you can loose one HDD on both sides and keep going

    the other way if you lost one HDD on both sides you would loose everything
    small detail but good one :)
     
  12. /dev/toaster macrumors 68020

    /dev/toaster

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    Feb 23, 2006
    Location:
    San Francisco, CA
    #12
    Don't buy the WD green drives!! They have an INCREDIBLY high rate of failure.
     

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