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  • need advice for RAID configuration

    Hello,

    need to build a file server with high read-write activity - recording and listening messages.
    The required storage capacity is 300GB.

    The server:

    Proliant DL380G7 x6 core 8 hard drives slots.

    I am planning to use 2 146GB 10k SAS drives in mirror for Windows 2008 and App.

    My question is about RAID for Data partition.
    Only 146GB SAS available with 15K speed. So I will go for it.

    What RAID type will be better:

    3 146GB in RAID 5 or 6 146GB in RAID 10 ?

    For RAID 5 I can put 4 146GB to have more spindels and drop one drive as hot spare.

    Appreciate your opinion.

    Michael.
    "When you hit a wrong note it's the next note that makes it good or bad". Miles Davis

  • #2
    Re: need advice for RAID configuration

    Well....


    RAID5 will give you higher read speed, but at a cost of slightly slower writes (because it needs to write parity)

    RAID10 would give you the benefit of writing/reading across multiple spindles at once, and then being mirrored..


    so i'd probably consider R10 as the better option here (or 0+1, either way)
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    • #3
      Re: need advice for RAID configuration

      I was more on R10 side too.
      There is other advantage like fast rebuild after failure.

      BTW, in R10 we can loose 2 or more drives (one in each mirror).
      Can I loose more than one drive in R5 with more than 3 drives?

      Thanks.
      Last edited by mla; 13th June 2011, 03:59.
      "When you hit a wrong note it's the next note that makes it good or bad". Miles Davis

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      • #4
        Re: need advice for RAID configuration

        RAID 10 can lose a whole mirror or drives within one mirror, but if it loses drives in each mirror, it is f***ed

        RAID 5 can lose 1 drive only -- if you can get RAID6 you can lose two
        (RAID 5 uses equivalent of 1 drive for parity, so you get n-1 drives worth of space. Raid 6 uses 2 parity blocks so you get n-2 drives of space)
        Tom Jones
        MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
        PhD, MSc, FIAP, MIITT
        IT Trainer / Consultant
        Ossian Ltd
        Scotland

        ** Remember to give credit where credit is due and leave reputation points where appropriate **

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        • #5
          Re: need advice for RAID configuration

          With Raid 10 you can lose up to two drives - if they're the wrong two, then you're in trouble. So while you get an extra bit of safety net, you still need to replace failing drives as soon as possible.
          Gareth Howells

          BSc (Hons), MBCS, MCP, MCDST, ICCE

          Any advice is given in good faith and without warranty.

          Please give reputation points if somebody has helped you.

          "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

          "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

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          • #6
            Re: need advice for RAID configuration

            With a 6 drive (3+3) RAID 10 you can lose 3 drives, as long as they are on the same "side"
            With 8 drives, you can lose 4 and so on
            Tom Jones
            MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
            PhD, MSc, FIAP, MIITT
            IT Trainer / Consultant
            Ossian Ltd
            Scotland

            ** Remember to give credit where credit is due and leave reputation points where appropriate **

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            • #7
              Re: need advice for RAID configuration

              Ossian,
              you say:
              RAID 10 can lose a whole mirror or drives within one mirror, but if it loses drives in each mirror, it is f***ed ---(FAILED )----

              I want to clarify that because I see it as follow (correct me)
              Let say we take 4 drives - 1,2,3,4.
              two Raid 1 are created:
              Logical drive 1 - drive 1 and 2
              Logical drive 2 - drive 3 and 4

              Then L1 and L2 are striped - Raid 0 applied. The first action was mirroring - R1, the second was striping – R0 . R1+R0= R10
              Now, I look at logical drive as a physical disk. If 1 physical fails in R0 - the END...

              But I can lose one drive in each mirror, regardless number of mirrors.


              And I just note that you present Raid 10 of 6 drives as 3+3. I see it as 3x2. That is why it brings some confusion to me.

              3+3 looks for me like Raid 0+1, where you first create a two striped (R0) sets - 3 disks in each and then mirror them (R1). So it will be R0+1 and not R1+0
              Last edited by mla; 12th June 2011, 10:09. Reason: adjusted the text
              "When you hit a wrong note it's the next note that makes it good or bad". Miles Davis

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              • #8
                Re: need advice for RAID configuration

                Any corrections on RAID 0+1 and RAID 1+0 drives failure option?
                "When you hit a wrong note it's the next note that makes it good or bad". Miles Davis

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