RAID Block Size for SSDs?

Discussion in 'Mac Pro' started by JesterJJZ, Sep 17, 2010.

  1. JesterJJZ macrumors 68020


    Jul 21, 2004
    I've looked at other threads but see so many mixed answers.

    I'm putting two Intel 80gig SSDs in my MacPro for boot in Raid0. What's the proper Raid block size to use. I'm assuming smaller in SSDs?
  2. nanofrog macrumors G4

    May 6, 2008
  3. Altimeter88 macrumors member

    Jul 17, 2006
    I have the same drives as you in RAID 0, I did a few google searches before doing it and I ended up going with 128K block size. I can't find the link but something to do with the x25m erase block size being 128K and wanting to match that.
    Anyway my system runs great with this setup. Here is a screenshot I just took:

    Attached Files:

  4. VirtualRain macrumors 603


    Aug 1, 2008
    Vancouver, BC
    +1 on 128K... I did a lot of research into this when I first got my drives and due to the write erase block size you want as large a stripe as possible to minimize write amplification. Most first gen drives had write erase block sizes of a brutal 512K while the Intels were reported to have block sizes of 128K. I'm not sure what current gen drives like Sandforce are using, as it's not a published spec that Ive seen, but you ideally want the stripe size to match the write erase block size or be as large as possible otherwise for optimal write efficiency.
  5. JesterJJZ thread starter macrumors 68020


    Jul 21, 2004

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